Unofficial Service Manual

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Overview

This describes the Zero motorcycle platform and includes as many service tasks not described (or incompletely described) in the official Owner's Manuals as customers have identified. Some information might be hearsay or not completely communicated, but attempts have been made to verify as much as possible. As with anything in a wiki environment, whatever you undertake with this as a guide is your own responsibility.

Unless otherwise stated, this manual refers to the shared S Platform and the 2013+ years in particular, as previous model years varied significantly and were produced in smaller numbers. It is a goal to cover the X Platform but progress here would benefit from volunteers invested in these models.

Contents

General Information

Platforms

Zero motorcycles benefit from some commonality around the powertrain. The motor, controller, BMS and MBB are more or less shared across all models, along with handlebars and controls.

S Platform

The S platform builds on a single evolving frame design around a full battery power pack, and consists of the S and DS and variants like the SR and DSR.

Fleet variants
SP, DSP, SRP, DSRP - Law enforcement / patrol.

X Platform

The X platform builds on a single lighter-weight frame design around two bricks of batteries, and consists of the FX and FXS variants.

Fleet variants
FXP, FXSP - Law enforcement / patrol.
MMX - Military built-to-order
Older variants
X, XU, and MX existed prior to 2014.

Lift

Some maintenance tasks are better performed with the wheels off the ground. The armored pan under the battery that protects onboard charging units is strong enough and positioned well to use a center lift.

Recommendation
Using a scissor lift center stand is an easy method to lift the bike.
Rage Powersports BW-1604A has been spotted at Zero HQ, but other manufacturers make very equivalent stands.
A center lift is easier than a rear stand to operate solo, and it is more compact than the rear stand although much heavier.
Location
Use a center lift under the rear of the battery compartment.
Strap the bike securely (through the center frame tube, say) to avoid toppling it.
Confirmed fits
Drag Specialties Center Jack (all models) uses a 15/16 hex wrench to raise and lower the lift.
MSR Pro Lift Stand for the FX, but not other models (even FXS) because of height issues.
Front Stand
The Zero does not offer axle attachment points for spools for a front stand.
The DS/DSR/FX models' front fender must be removed to use a pin for the front steering head; pin diameter unconfirmed.
The S/SR model pin diameter is 5/8"
Rear Stand
The Zero does not offer swingarm attachment points for spools for a rear stand.
A rear stand can work if it cradles the underside of the swingarm snugly. This can work but takes a little care to operate single-handedly.
Confirmed fits: Pit Bull Standard Rear Stand, Haul-Master 1000 Lb. Capacity Motorcycle Swingarm Rear Stand (Harbor Freight)
An axle stand can be fabricated, like this Home made rear axle stand on Zero FXS.
References

Tools

Tools and parts to support your bike

A travel kit for a motorcycle is always a good idea, but Zero doesn't include a default set. They do sell a tool kit which covers many common tasks.

From riders, these seem like the useful set to bring:

  • Allen wrenches (3mm for tank plastics, 4mm, 5mm)
  • Torx T45 for MY2015+. See: Unofficial Service Manual#Seat
  • Tire pressure gauge.
  • Tire patch kit, suitable for tubed or tubeless tires depending on your model/year.
  • Spare 12V fuses (10A, 15A typically).
  • 10mm, 13mm wrench (for belt tension adjustment and?)
  • Cable ties.

Spare parts for long travel rides:

  • Belt
    Gates GT Carbon, 14mm wide, 8mm pitch, 220 teeth ~$90, only available from Zero.
    Expect to eventually use it as replacement, helps avoid waiting on delivery).
  • Eaton JJN-100 fuse or size-matched 200V-rated fuses (30A will do in a pinch, being lower-spec) for high-voltages circuits like the accessory charging circuit which can be circumstantially blown without compromising the main boards.

VIN

This helps aggregate all the VIN guides across the manuals for cross-referencing.

VIN Decoder Ring
Year Manufacturer ID Motorcycle Type Model Line Net Brake Power Check Digit Model Year Plant Location Model Serial Number
2009 538=Zero Motorcycles, Inc.
S=Street
C=Commuter
2=168 Cell
3=2nd Generation
4=336 Cell
05=0-50hp
51=50-100hp
10=100+hp
1-digit calculated 9 C=California
Scotts Valley
1
5-digit yearly serial
2010 A
2011
S=S/DS Platform
(Z1 in manual)
X=X/MX Platform
(Z2 in manual)
M2=S
D2=DS
U1=XU
U2=XU-LSM
X0=X
X1=X
M0=MX
E1=MX
M1=M/16.2 (19.8hp)
A1=A/26.1 (31.9hp)
B
C=X
D=MX
E=XU
F=XU-LSM
1=X
2=MX
2012
M3=S
D3=DS
L2=XU-M (EU)
U2=XU
C2=XU-LSM (CA)
X2=MX
M3=9.1kW
C
A=S
B=DS
C=XD/X
E=XU
E=XU LSM
2013
S=S/DS Platform
X=X/MX Platform
M4=S
D4=DS
X3=FX
U3=XU
Z1=13kW
D
A=S
B=DS
C=XD/X/FX
E=XU
2014
S=S/SR/DS Platform
X=X Platform
M4=S/SR/SP 8.5
M5=S/SR/SP 11.4
D6=DS/DSR/DSP 8.5
D5=DS/DSR/DSP 11.4
X4=FX/FXL
X5=FXP/FXLP
Z1=13kW
Z2=16kW
E
A=S/SP
B=DS/DSP
C=XD/X/FX/FXL
G=SR
H=FXP/FXLP
2015
M7=S/SR/SP 9.4
M8=S/SR/SP 12.5
D7=DS/DSR/DSP 9.4
D8=DS/DSR/DSP 12.5
X6=FX/FXS
X7=FXP
F
A=S/SP
B=DS/DSP
C=FX
G=SR
H=FXP
2016
S=S/SR/DS/DSR Platform
X=X Platform
M0=S/SR/SP 9.8
M9=S/SR/SP 13.0
D0=DS/DSR/DSP 9.8
D9=DS/DSR/DSP 13.0
X8=FX/FXS
X9=FXP
Z1=13kW
Z2=16kW
Z3=16kW IPM
G
A=S/SP
B=DS/DSP
C=FX
G=SR/DSR
H=FXP
J=FXS
2017
MB=S/SP 6.5
MC=S/SR/SP/SRP 13.0
MD=S 13.0 (11kW)
DA=DS 6.5
DB=DS/DSR/DSP/DSRP 13.0
XB=FX/FXS/FXP
ZA=11kW 75-5
ZB=11kW 75-7
Z2=16kW 75-7
Z3=16kW 75-7R
Z4=17kW 75-5
Z5=21kW 75-7
Z6=21kW 75-7R
H
A=S/SP
B=DS/DSP
C=FX
G=SR/DSR/DSRP
H=FXP
J=FXS

Frame/Body Panels

Frame

S Platform
The 2013+ Zero frame for S/DS/SR/DSR bikes is made of anodized aluminum, weighs 23lbs, and is a combination of cast parts and welded square tubing of 1-inch outer width.
The frame slips onto the battery pack case over the top and attaches to it with four major bolts around the bottom. The charger is attached to the underside with a protective plate covering it (plastic for S/SR, aluminum for DS/DSR).
Attachment Points
The frame offers a number of rivet nut attachment points for the lower plastics.
The rivet nuts are sized to accept M5 bolts (a total depth of 20mm is available without marring the inside of the frame bar) with a 6mm shoulder to a depth of 5mm. (A longer shoulder and length are required for fastening a bracket beyond that.)
From 2015 onwards, the frame has extra attachment points made for the crash bars used for fleet/police models.
Two extra rivet nut holes on each side of the frame diagonal shoulder of the same size. They are 30mm apart (center to center).
The lower bash plate has similar modifications from that year - two rivet nut holes pre-made for M6 bolts and capped by threaded plastic inserts on each side for the lower mount. There is perhaps 10mm thread depth or allowance between the outer surface of the plate and the onboard charger enclosure.
On prior year models, the OEM or dealer would make these fittings.
X Platform
The 2013+ Zero frame for FX/FXS (and X/MX/XU) bikes is made of anodized aluminum, weighs 20lbs, and is a combination of cast parts and welded square tubing of 1-inch outer width.
The frame fits two power pack modules, or one module and an empty space for carrying small cargo.
The FXP fleet model has a crash guard mount option like the SP/DSP models but is smaller and mounted lower.
Paint matching
All models have the same anodized aluminum with a black finish/paint.
Some paint repair suggestions on this thread are worth examining: FX frame touch up
Iterations by Year
Each year's frame from 2013 onward is incrementally improved and stronger than the prior year.
The 2014 frame changed up the way the side plastics bolt on and provides for the power tank via the carrier bracket.
The 2015 frame included pre-drilled holes for the crash guards for fleet/police models.
The 2016 frame seems to be a little more built-up and has additional members bracing the diagonals to the main beams behind the shoulder.

Kickstand

The kickstand is made from cast aluminum and swings outward from the left side.

There is a safety interlock switch at the pivot that prevents the motor from operating when the kickstand is down.

Kickstands
Years Model Length Part no
2013-2014? S/SR shorter than the DS/DSR 20-05660 03
DS/DSR 10.8" / 275mm 20-05661 03
FX 15.0" / 380mm 20-05662 03
FXS
2015+ FX 13.5" / 343mm
FXS 11.8" / 300mm

Both DS and FX kickstands are identical from the spring screw up to the pivot, and should interchange.

All the 2013+ kickstands uses the same pivot pin & spring.

References
Re: 2016 FXS Lowered Ride Height OEM Shock, Dual Use Tires, Drop Bars, Hand Guards,
Help needed: Kickstand "bent"
Mounting
3/8" E clip, Zero part no 90-0283700, also available generically.
Clevis pin custom, Zero part no 90-0279900.
Mounting bracket, custom
Maintenance
The official manual recommends keeping the pivot greased as necessary with a six-month check interval.
Replacement
Tools
  • Centerlift.
  • Large flat-blade screwdriver or specialized tool like drum brake spring pliers for spring removal and replacement.
  • Needlenose pliers for the 3/8" E-clip.
Steps
  1. Place the motorcycle on a center lift.
  2. Remove the kickstand
    1. Pull the spring off of the kickstand hook with a large flat blade screwdriver or a specialized kickstand spring release tool.
      Be extremely careful working with the kickstand spring as it is under high tension. A specialized tool makes this easier.
    2. Pull the E-clip off of the inside of the pivot.
    3. Remove the pivot pin.
    4. Remove the kickstand.
  3. Perform the above steps in reverse (sic)
    1. Place the new kickstand onto the pivot.
    2. Clean the pin and apply fresh grease to it.
    3. Insert the pin and fasten it with a new 3/8" E-clip.
    4. Raise the kickstand to its stowed/horizontal position, where the spring requires the least amount of force/extension to install.
    5. Install the spring over the kickstand hook with a suitable tool (see tools requirements).
      Note: This is the most difficult and dangerous part of the job.
      Use eye protection while doing this and ensure your hands won't be damaged if the spring flies back while getting it over the hook.
      Focus on applying steady force with as much leverage as possible to extend the spring back along the swingarm.
      One trick is to use a strong line looped through the hook as a pulley.
      Another trick is to bend the spring enough back and forth to insert pennies between the coils, which holds it in an extended position. Then loop the spring over the hook and pull the pennies out with pliers.
  4. Check the operation of the kickstand a few times.
  5. Put the kickstand down before letting the motorcycle off the lift to rest on it.

Panel Material

Zero body panels are made from ABS plastic.

2013-2016
The plastics' color is molded-in, and so it fades over time with sun exposure. On the other hand, they're relatively inexpensive to replace from Zero; ask your dealer.
Some use Plexus plastic cleaner to keep them polished successfully.
POLYTROL Colour restorer could help with color restoration.
Retr0bright solution developed for restoring 1980's yellowed ABS personal computer chassis material may be of use, unconfirmed.
2017+
The plastics as of this model year are painted rather than molded-in.

Seat

TOPRACKKIT10-0692107 seatfastener.jpgMY2016DSR seatfastener withtoprack.jpg
The stock seat is held in place by two features:

  • A metal bracket with holes for retaining bolts that mount through the frame from the outside.
    The bracket also serves to align the seat horizontally since the outer sides of the bracket must slide directly along the inside track of the frame.
  • A pair of sliding catches at the front of the seat that slide under cylindrical tabs extending from the frame centerpiece.
Removal
Model years 2015+ require a T45 Torx wrench to extract.
For 2013-2014 models, after installing the top or side racks, this changes to M8x50 bolts requiring a 5mm Allen key wrench.
  1. Remove the seat bolts.
  2. Pull the seat back and out.
Dimensions
  • Seat
  • Seat Bolts
    M8 with 1.25mm thread, 50mm long with a round end for aligning the seat bracket with the frame.
    With the top rack installed, the diameter of the hole around the head is slightly under 15mm, with a maximum offset of about 12mm.
  • Seat Bracket Bolts to Seat Pan

When luggage racks are installed, these bolts are generally load bearing (or at least damping), so unload the racks before taking the seat off for an extended period of time to avoid stressing the racks.

When putting the seat back on, make sure to align the seat's bracket with the frame holes to avoid wear. If the top rack is installed, too, check the alignment of that as well to avoid wear trying to thread the bolts.

Tank Plastics

Fasteners
Zero plastics all are fastened with blackened M5x15mm mushroom cap socket head bolts using a 3mm allen key wrench.
All have black plastic washers with 5mm inner diameter, 10mm outer diameter, roughly 1mm thick.
Removal
Patrick Truchon's Under the Hood notes show photos of removal with simple instructions.
Keep removed fasteners and washers organized so you don't lose them.
Tools
  • 3mm allen key wrench.
  • PH2 Philips Head screwdriver, preferably a compact side-ratcheting tool or a very long tool to reach across/through the steering head area.
Steps
  1. Remove the seat.
  2. Use the 3mm allen wrench to loosen both bolts at the rear of the "tank" around the frame centerline. They have washers to mind keeping.
    SDS12VACCESSORYSOCKETKIT14MY10-0750401 removetankplasticscenterline3mm.jpg
  3. Use the 3mm allen wrench to loosen 2 bolts at the front of the tank around the lock / handlebars. They also have washers.
    SDS12VACCESSORYSOCKETKIT14MY10-0750401 removetankplasticsnearlock3mm.jpg
    At this point, the flexible plastics attaching the tank to the front of the frame allow lifting the tank slightly if that is enough for your purposes.
  4. Use the Philips-head screwdriver to loosen the three screws on each side of the front inside of the tank.
    SDS12VACCESSORYSOCKETKIT14MY10-0750401 removetankplasticsfrontinsideph2.jpg
    The topmost screws have washers.
    The bottommost screws are the most inaccessible, recessed in a narrow slot in the plastics. A special tool is most needed here, especially with a DS/DSR to clear the fender. E.g Chapman Mfg #1916 or Wadsworth Falls Mfg Co,
  5. Lift and remove the tank plastics.

Tank removal 2016 DSR.jpgSDS12VACCESSORYSOCKETKIT14MY10-0750401 overallviewlefthandside.jpgSDS12VACCESSORYSOCKETKIT14MY10-0750401 overallviewrighthandside.jpg

Construction
All variants of the tank plastics for have identical side pieces and a black centerpiece in soft plastic with a relatively rough finish.
The stock centerpiece for 2013-2016 models is a bin container with two drain holes for collected moisture, with a soft bin held together with a simple zipper that anchors via hook-and-loop patches at the bottom of the bin as well as a loop cord that hooks through the front helmet lock.
The bin delivered per model year is different and varies in quality. 2013 seemed to have better construction than 2014-2015 years, and 2016 is somewhere between.
As of 2017, the stock centerpiece is a locking storage container with a spring-loaded hinge at the front so it swings forward to open.
The Power Tank and Charge Tank have tank plastic options which can be bought separately or selected for color customization. Both use a relatively flat surface for the centerpiece, and the Charge Tank has a J1772-sized inlet hold with built in waterproof cover with a spring-loaded hinge.
Separating
The join between the centerpiece and side pieces of a Zero tank plastic assembly is made by plastic weld using a soldering iron into soft hollow plastic pins on the centerpiece that melt and flatten around a lock washer onto holes in the side pieces.
You can break these welds using a relatively careful use of a pair of pliers to basically grip hard and twist on them until they break.
It's a slightly frustrating process but pretty quick to achieve, in about an hour. A soldering iron or extremely narrowly-focused heat gun can help the process but try not to risk damaging the plastics from overheating.
The original join process can be repeated for the new centerpiece.
Also, this means that the plastic centerpiece you remove will not be re-joinable.

Tail Plastics

Removal
You'll be disconnecting the rear lighting wiring and removing the tail subassembly, and then removing the tail plastics from that.
Tools
  • 3mm, 4mm, 6mm Allen wrenches.
  • For the seat bolts: T45 Torx wrench (without top rack) or 5mm Allen wrench (with top rack).
  • Phillips screwdrivers.
  • Needle nose pliers.
  1. Remove the seat.
  2. Remove the black seat pan bolts and nylon washers with the 3mm Allen wrench (lower on the side near the hollow frame tube).
  3. Use a Philips screwdriver to unscrew the bolt holding down the rear of the plastic controller cover.
  4. Cut the cable ties around the signal wires on the left side of the seat area behind the controller.
  5. Disconnect the turn signal wires and brake light / plate light wires.
  6. Remove the 4 bolts that hold tail frame with a 6mm Allen wrench. This detaches the tail frame.
  7. Remove the tail extension using a 4mm Allen wrench. Mind the turn signal wires that go through holes here; draw them through.
  8. (TODO more stuff to remove in there, unsure what's necessary or how)
  9. Remove the black tail enclosure plastics from the cosmetic plastics; there seem to be tabs?
  10. Use a Philips screwdriver to remove 5? screws holding the cosmetic plastics to the frame from underneath.
  11. Use a 3mm Allen wrench to remove the two screws holding the cosmetic plastics to the top of the frame.
Reassembly

Note: I didn't document the disassembly because I had to fumble around a lot. But I documented the reassembly, which can probably be done in reverse. If someone wants to confirm that this works and re-edit this section, that would be great.

There were 5 pairs of bolts to remove:

ZeroTail01.jpg

ZeroTail02b.jpg

With the tail light off, bolt the top plastic to the metal frame.

ZeroTail03.jpg

Clamp the bottom tail plastic and screw in the 5 screws that hold both pieces together

ZeroTail04.jpg

Here is how the black tail plastic fit with the tail light. Notice the "zipper" down the middle. There's also a very small one on top of the tail light. On the outside are the tabs that clip into the coloured plastics.

ZeroTail05.jpg

ZeroTail06.jpg

Loosely bolt the end of the black tail plastic to the frame. Note the small nut that's between two fins of the controller. It can easily be held with a pair of pliers.

ZeroTail07.jpg

Rotate the pieces up and temporarily (and loosely) attach them to the frame.

ZeroTail08.jpg ZeroTail09.jpg

To bolt the tail light, remove the temporary bolts from the previous step and push a driver down through the plastic (because of the angle of the taillight bolts).

ZeroTail10.jpg ZeroTail11.jpg

"Zip" the plastic back together. There's also a tab on top of the tail light that must be fitted properly.

ZeroTail12b.jpg

I added duck tape to seal the interior of the compartment to keep it cleaner.

ZeroTail13b.jpg

Snap the clips on the coloured plastic. Note that it's not the coloured piece that should move but the black piece. I found it helped to have one hand inside and one hand outside to fit the pieces together. There's also two clips at the end on top of the taillight.

ZeroTail14.jpg

Loosely bolt the tail and fit the wires back through the small hole.

ZeroTail15.jpg

Add a new zap strap and tidy things up.

ZeroTail16.jpg

Note that before disconnecting the wires, I took a picture of the set up to be able to match the colours. In my case, red goes with green and white goes with grey. This may be different for your bike.

ZeroTail17b.jpg

Fasten all the loose bolts.

ZeroTail18.jpg

Re-attach the top and side racks if applicable.

ZeroTail19.jpg

Lower Plastics

Lower plastics for 2012-2013 are relatively angular and have their own bolt mount pattern.

2014+ model lower plastics have a sculpted re-design to deliver more airflow to the motor for cooling.

2017 ZF6.5 models have lower plastics with a latch and swinging hinge to access the storage area behind the half-size battery compartment.

Removal
For 2014+:
Adapted from this forum post.
  1. Use a 3mm allen wrench to unscrew the three M5 bolts holding each side panel: one at the top front corner, and one at each corner near the lower edge.
    Lower plastics bolt1.jpgLower plastics bolt2.jpgLower plastics bolt3.jpg
  2. Remove each side panel.
    MY2016DSR sideplastics removal.jpgLower side plastics removed.jpg
  3. Use a 3mm allen wrench to unscrew the 2 bolts on each side holding the front panel on and remove it.
For 2012-2013:
  1. Use a 3mm allen wrench to unscrew the three M5 bolts holding each side panel.
  2. Use a ball-point pen or similar non-scratching pointed tool to push the center pin to release the plastic rivets on the front panel and remove it.

General Maintenance

Headlamp

Zero's models ship with halogen bulbs.

X Platform Headlamp

Prior to 2014, the headlamp was a generic circular reflector unit.
In 2014, the FX acquired a dual projector configuration with a W3W stock running light.
Adjusting angle (2014+)
There are two retaining bolts on each side of the headlamp assembly.
Loosen all four bolts, pivot the assembly to the angle as desired, and then re-tighten to fix it in position.

S Platform Headlamp

Prior to 2012, the headlamp was a generic circular reflector unit.
For 2012+ models, the Zero's stock headlamp assembly is the LSL Urban Headlight with an H4 bulb in a 9003 / HB2 socket, and a W3W stock running light.
LSL Urban headlight housing dimensions: 190mm width, 260mm height, 125mm depth.
The headlamp housing OEM is by TRIOM with part number T7869010. It can be bought on the Italian market (ebay.it or amazon.it or such) for $100 instead of $160 in the US.
Power
The stock headlamp draws about 55/60W which is the largest regular 12V electrical load by default.
The electrical load doesn't impact range much (110Wh over 2 hours compared to 11+kWh yields 1% range difference), unless you ride a very slow long travel leg for, say, offroading.
However, it does heat up the housing glass.

The headlight is fastened in by a plastic bracket that locks when rotated, and covered with a rubber boot to protect from moisture.

Removal
  1. Unbolt the two lower mount screws with a 4mm Allen wrench.
  2. Unbolt the two upper mount screws with a 3mm Allen wrench.
  3. Disconnect the headlight and running light wires to detach the assembly completely.
Adjusting angle (2013+)
There is a set screw on the upper back of the headlamp housing to adjust the angle of illumination.
Adjust this while the bike is sitting fully upright.
Remove the lower screws and swing the headlamp on the two upper bolts to access the screw while adjusting.
Turn clockwise to raise the angle, counterclockwise to lower.

Signals

Always check for functioning signals (running light, headlamp, turn signals, brakes).

Turn Signal Bulbs
2013+
Type PY10W, similar to 1156, but the side pins are offset by 150 degrees rather than 180.
Also called BAU15S or R10W.
The glass is amber (as the lenses are clear) and smaller, since the regular 1156 glass is too big.
2009-2012
Clear 1156 incandescent bulbs, very standard.
Turn Signal Flasher
The turn signal ("blinker") flasher is a simple three prong flasher relay.
It's attached directly by a plug so is easily replaced if it fails (or for an LED compatible unit).
Flasher Location
2012: Under the seat below the fuse block.
2013+ X Platform: Behind the right fairing.
2013+ S Platform: In front of the front plastics area under the frame "wishbone" with other electrical connections.

Fasteners

Always check for loose or corroding bolts.

Use blue Loctite threadlocker for non-conductive bolts.

TODO: recommend a corrosion inhibitor.

Mirrors

Design
Pre-2015 Zeros use an angular mirror with a ball mount joint that allows rotating the mirrors 360 degrees.
Many riders turn the mirrors upside down for a little wider visibility around the shoulder/arms.
2015+ Zeros use a mirror stalk with an inboard ball mount with about 30 degrees of freedom from the stalk.
Mount
Zero mirrors are mounted from the handlebars with Yamaha/Ducati-style bolt fitting.
The bolt/thread specification is M10x1.25, left-hand-threaded on the left side and right-hand-threaded on the right side.
Maintenance
(pre-2015) Check that the set screw holding mirror position holds it firmly.
Use a corrosion inhibitor or thread-locker for the set screws and the mount threading since these are weather-exposed.

See Third-Party Mirrors for workable/tested replacements.

Front Wheel/Suspension/Steering

Ignition

The ignition wiring connects to a ZADI motorcycle lock with a steering lock feature and parking light enable (although the parking light enable is not connected on the Zero).

Key blanks appear to be available as JMA ZA9P1 FOR ZADI ZD23RCP.

Occasional lock lubrication is recommended, and inspection of the wires for startup enable on the underside of the lock for reliability.

See also #Faulty Ignition Switch for issues with this.

Lock

The lock for the tank bag (2013-2016) or tank compartment (2017+) and possibly a helmet is keyed the same as the ignition.

The lock is mounted to the frame by two (M5?) bolts under the steering head, very difficult to access without taking much of the frontend apart (as it should be, for theft deterrence).

Handlebars

Both S and DS style handlebars are standard through bars that are 1 1/8" (28mm) through the middle section and 7/8" (22mm) in the outer section.

Clamps
The handlebar clamps are 2" by 1 1/8" (28mm) for the entire line of models, clamped with M10 bolts (50mm length).
Switch Assemblies
The switch assemblies are fastened with TT20 (1/4 inch) tamper-resistant Torx bolts through the underside.
Bar Ends
2013 models bar ends are covered by the grip so are not easily changed without changing the grips.
Zero did offer heated grips for these models but dropped them after changing the bars in 2014.
For 2014+ models, any bar end accessories that match the 14mm inner diameter will fit; the stock bar ends are round plastic bumpers held in by plastic threads, so can be removed with a little twisting and pulling.

Brake Lever

Zero motorcycles have a right-hand lever for the front brake, as is common for motorcycle designs.

Primary adjustment
The brake lever has a dial for adjusting the lever position relative to pad pressure and rider finger reach; set it however lets you operate it comfortably and safely.
Micro-Switch and Set Screw
A set screw on the inside of the lever adjusts how a micro-switch is depressed.
The micro-switch is what activates the rear brake light and the "braking regen" mode at the same time.
Any adjustment or replacement of the brake lever should be followed by recalibrating this set screw to get the desired effect.
Too much free play and the switch will activate when going over bumps and result in a slightly jerky ride.
There is some guidance on how to adjust this: Brake Lever Regens before Pad Contact.
It seems like there's small difference in how this set screw is secured in stock lever compared to replacement lever (2016 SR), even though they look identical. I wasn't able to adjust this screw on stock lever, however replacement lever adjusts with no issues. You will need 7/64 SAE hex key to adjust.
Use some light threadlock compound (Blue Loctite will do) to fix the set screw in the desired position if it seems to move too freely out of the desired range.

Front Suspension

Front Suspension Parts

Fork sizes
Years Brand Description Models Travel
2013-2014 FastAce 43 mm inverted forks with adjustable compression and rebound damping S/SR 6.25 in (159 mm)
DS 7.00 in (178 mm)
2015-2017 Showa 41 mm inverted cartridge forks, with adjustable spring preload, compression and rebound damping S/SR 6.25 in (159 mm)
DS/DSR 7.00 in (178 mm)

TODO: list the following:

  • fork spring rate / length / diameter
  • torque specs for fork, axle, clamps and steering head.
  • Any forks that cross-over / substitute directly.
  • Any triple/fork combo that crosses over.
Adjust Suspension Preload
TODO
Fork Oil Level Note
Measure from outer tube end to oil surface (Condition: spring, spring joint, spring collar, seat rubber, slider, fork bolt are removed and dust seal touches axle holder)

Front Wheel Axle

TBD
  • front wheel bearing size
  • front wheel spacers

Steering Head Bearing

Steering stickiness or wobble may indicate an inadequately greased steering head bearing or a worn bearing.

Reference
ZeroDS head bearing (2015)
TBD
  • steering head bearing size by platform/model/year

Front Suspension Specs

Suspension Specs
Years Manufacturer Fork Material Model Fork Part# Fork Measurements Oil Shock Material Shock Part# Shock Measurements
2009-2010 FastAce DS/X BDA53AR (discontinued)
2013-2014 FastAce

6061-T6 Forged Aluminum (per this thread) Chrome-Moly inner tube; Alloy steel spring wire

S/SR ALX07RC (discontinued)

6061-T6 Forged Aluminum (per this thread)

BDA58RC (discontinued)
DS
Left
22-06093-02?
Right
22-06094-02?

(APX05RC? or APX10AR? (discontinued))

Distance
900 mm
Travel
220 mm
BFA57RC (discontinued))
Rebound Adjustment
12 clicks
FX/MX/XU
2015-2017 Showa
Outer Tube Finish
Natural Anodized (silver)
Slide Tube Finish
Nickel - Hard Chrome
Rebound (Tension) Finish
Black Anodized
Compression Finish
Black Anodized
S/SR
Free length
461.5mm.
Outer diameter
36.2mm.
Stock spring rate
7.4 N/mm
Type
SS-8
Level
117 mm
Body Finish
Natural Anodized (silver)
Rod Finish
Nickel - Hard Chrome
Rebound (Tension) Finish
Black Anodized
Compression Finish
Black Anodized
DS/DSR
FX
Left
22-05868-02
Right
22-05869-02
Free Length
789.1±2.0mm
Max Length
798mm
Min Length
580mm
Stroke
218mm
Spring Rate
5.4 N/mm
Rebound (Tension)
Max - 9 clicks
Compression
Max - 5 clicks
Preload
Min + 3.0 turns
Type
SS-8
Volume
442±2.5cm3
Level
103mm
22-05879-02
Spring Rate
73.6-82.4 N/mm
Free Length
320±2.0mm
Max Length
320.5mm
Min Length
246mm
Stroke
74.5
Rebound (Tension)
Max - 12 clicks
Compression
Max - 9 clicks
Preload
2nd Position
FXS

Fork Oil Change and Spring Replacement

FastAce fork oil change / spring replacement part 2 by Ray Ivers

Tools
  • 7mm Allen wrench for riser bolts.
Steps
  1. Put the motorcycle on a stand.
  2. Remove the risers and handlebars using a 7mm Allen wrench.
  3. Loosen the fork caps, front axle, and brake caliper bolts while the front wheel is on the ground.
  4. Fork cap / spring removal...
  5. Oil change...
  6. Fork spring / cap replacement...
Notes
Torques
What Torque Bolt
Handlebar clamps 15 ft/lb M8
Handlebar risers 25 ft/lb M10
Triple clamps (all) 15 ft/lb M8
Fork caps 15 ft/lb M46
F caliper bolts 18 ft/lb M8
F axle end cap 15 ft/lb M8
F Axle clamps 9 ft/lb M6

Verify Fork Spring Rate

How to Verify Fork Spring Rate

  1. Add a zip-tie to the the fork tube.
    • Make sure it is snug so it stays in the place it was last pushed too.
    • Once the zip-tie is on the fork tube, you push it up to rest it against the upper fork.
  2. Measure bike sag (unloaded)
    Lift the front fork off the ground and measure the gap (zip-tie to fork gap) created by the front weight of the bike.
  3. Measure rider sag (loaded)
    1. Now push zip-tie back up the fork, then sit on the bike and raise your feet so all of your weight is carried through the suspension.
    2. Then carefully dismount and put kickstand down.
    3. Measure the gap (zip-tie to fork) created by your weight.
    4. Add this gap measurement to the bike sag measurement, this is the total sag.
    This measurement should be around 25% of the working range of the front suspension.
    Now that is a guideline; it can be higher or lower than 25%.
    It depends on what is happening when you are loading up the suspension (upper end).
  4. Checking the upper end by using the zip-tie.
    After riding, check the location of the zip-tie: the gap from the fork to the zip-tie.
    Lets say the measurement is 5". Then you would know the total max travel used was 5" + bike sag measurement.
That total measurement should never equal the total suspension travel amount (6", I think based on your posting).
  • If it equal, then you are bottoming out. Increase the preload and see if this keeps you from bottoming out.
  • If you use max preload and are still bottoming out, you will need stronger springs.
  • If you find you are only using 75% to 80% of the max suspension travel, you can reduce the preload spacer length some or you can live with this.
  • If you are only using ~50% or less of the suspension travel, your springs are probably too stiff. You should swap springs to a lower rate spring.

Front Wheel

Front Wheel Removal

Tools needed
6mm Allen Wrench - Axle bolt (M17)
5mm Allen Wrench - Pinch
13mm Socket - Brakes
Steps
  1. Loosen both brake bolts using the 13mm socket.
  2. Loosen both right pinch bolts using the 5mm allen wrench. Alternate slightly, turning each counter-clockwise.
  3. Loosen the axle bolt using the 6mm allen wrench.
  4. Loosen both left pinch bolts using the 5mm allen wrench. Alternate slightly, turning each counter-clockwise.
  5. Securely lift the front wheel.
  6. Remove both brake bolts using the 13mm socket, and lift and secure the brake caliper without stressing the brake lines.
  7. Continue to back off the pinch bolts, but do not remove, using the 5mm allen wrench.
  8. Remove the axle bolt and outer spacer using the 6mm allen wrench.
  9. Replace the axle bolt with the 6mm allen bolt, turning several turns inward, without the outer spacer.
  10. Push on the axle bolt while encouraging the left side of the axle out.
    Support the wheel to reduce binding!
  11. Remove the axle.
  12. Remove the wheel.

Front Bearings

The front bearings are the same size as the rear bearings (see table there for sizing), although the front has only two bearings instead of 3 for the rear.

Front Bearing Replacement

Tools needed
6mm Allen Wrench - Axle (M17)
5mm Allen Wrench - Pinch
13mm Socket - Brakes
Bearing Press Tool/Kit
Steps
  1. Remove the Front Wheel per steps above
  2. Remove the spacers, then the dust seals, from each side and clean.
  3. Press the bearings out from the opposite side.
    A socket extension works well, alternating around the perimeter.
  4. Clean the inner wheel.
  5. Press the new bearings in, aligning with the inner axle tube.
    A large socket works well to press only on the outer bearing.
  6. Replace the dust seals.
  7. Return the wheel to the bike.
  8. Aligning the axle with the spacers, press the axle back into the forks.
  9. Expand the brake calipers to prepare for remounting.
  10. Remount brake caliper with the 13mm socket to the correct torque.
  11. Return the outer spacer and make the axle bolt snug with the 6mm allen wrench.
  12. Alternate tightening each 5mm pinch bolt.
  13. Ensure proper wheel movement.
  14. Tighten left pinch bolts to the correct torque using the 5mm allen wrench.
  15. Tighten the 6mm Axle bolt to the correct torque.
  16. Tighten right pinch bolt to correct torque using the 5mm allen wrench.
  17. Ensure smooth movement.
  18. Pump the brakes to return to proper action.
  19. Lower the front wheel.
  20. Confirm torques.
  21. Test ride!
  22. Reconfirm torques.
  23. Paint the bolt heads to so that any loosening is detectable.

Final Drive

Rear Shock

Years Brand Model Description Media Specs Models Travel Length
2013-2014 FastAce BDA58RC Piggy-back reservoir shock with adjustable spring preload, compression and rebound damping
2013 S Rear Shock FastAce BDA58RC
Spring Rate
550 ~ 805 lbs/in
Spring
Length 142mm, Diameter 57mm
S/SR 6.35 in (161 mm) 10.25-10.5 in (260mm)
DS 7.03 in (179 mm)
2015-2017 Showa 40 mm piston, piggy-back reservoir shock with adjustable spring preload, compression and rebound damping S/SR 6.35 in (161 mm)
DS/DSR 7.03 in (179 mm)
Substitutions
  • 2013-2014 rear shock sizes seem to match the Yamaha R3, which has a number of supported replacements.


Adjustment
The Official Manual section on Rear Shock Adjustment illustrates how to measure preload and check sag.
Compression
The official manual's description here is adequate and this can be done readily by hand on the right side of the bike at the top of the shock.
Rebound
The adjustment knob is at the bottom of the shock facing rear, as described in the manual, and can be worked by hand or with a wrench with a careful reach into that area.
Spring Preload
The official manual illustrates the collar and procedure for spring preload adjustment, but does not recommend a specific tool, and there are clearance issues in that area for tools.
The adjuster sleeve diameter is 58mm (2.3").
A Stockton spanner wrench was found to be suitable for the job if modified as follows (per 2017 DSR Showa rear shock spanner wrench):
  • Grind the nose of the wrench to fit the notches.
  • Bend the wrench a couple of degrees to clear the Sevcon motor controller fins.
Obviously, a better solution is still worth seeking.

Rear Brake Actuator

The rear brake is manipulated by a dirt-bike style pedal around the right footpeg, a common motorcycle configuration.

The rear brake has its own master cylinder behind the rear footpeg on the right.

Pedal Construction
Cast aluminum with a powder coat finish.
On pre-2015 models, the pedal is made from a single piece.
On 2015+ models, the pedal toe actuator is bolted on and may be replaced.
Rear Brake Lever/Pedal
The threaded rod from the brake lever to the master cylinder adjusts lever height.
Rear Brake Switch
The rear brake switch is activated hydraulically by pressure in the rear brake system.
The rear brake switch is built into top banjo bolt.

Ref. [1]

Rear Wheel

Check Tire Pressure

Maintain minimum pressure per the manual.

General guidelines
Higher tire pressures help stability and reduce rolling resistance with a passenger or a lot of luggage, but lower pressures help on rougher/gravel surfaces.
Official recommendations are for "cold" tires, which means when they haven't been ridden in a few hours.
As tires warm up from riding, pressure increases due to the interior air heating from friction and mechanical work on the tire by the road against the wheel.
Excessive tire pressure can make the tire too sensitive to sharp debris or potholes, and increases the risk of a puncture. 45psi is where this definitely becomes a concern; modulate depending on your riding, and definitely use much lower pressures for offroading.

Rear Wheel Removal

Tools
27mm socket
Breaker bar
Instructions
  1. Place the motorcycle on a lift or rear stand so the wheel spins freely.
  2. Mark/photograph where the alignment marks reside on each side of the axle for re-alignment when re-installing the wheel.
  3. Loosen the rear axle nut on the right side (27mm) with the breaker bar.
  4. Remove the rear axle nut.
  5. Pull the axle part-way out so that the wheel can be moved forward enough to loosen the belt.
  6. Pull the belt off of the rear sprocket and let it hang outside of the swingarm slightly to avoid interfering with the wheel.
  7. Pull the axle through the wheel from the left side.
  8. Set aside the spacers with alignment marks, noting which goes on which side.
  9. Set aside the axle and axle nut.
  10. Pull the wheel out behind the swingarm.
    The license plate tail holder will likely require rolling the wheel out at an angle to clear it.

Rear Wheel Install

Tools
27mm socket
Torque wrench set to 75ft/lbs or 102nm
(Optional) rubber mallet to nudge the axle
Instructions (also see belt adjustment procedure)
  1. Ensure that the axle has grease applied if it is dry, to minimize friction and wear against it under load.
  2. Push the axle through the alignment bracket and left swingarm until flush on the inside of the left swingarm.
  3. Place the rear brake caliper holder onto the right swingarm.
  4. For 2015+ models, place the ABS rear wheel speed sensor on the inside of the rear brake caliper holder.
    Route the wire feeding the speed sensor around the caliper holder bracket and ensure that the sensor and wire will install without tension or excessive bending.
  5. Roll the wheel into position inside of the axle.
    Ensure the speed sensor on the right side mates with and covers the rear wheel bearing before it aligns with the rear brake caliper holder on the right side, as this "sandwiches" together.
    Ensure that the brake calipers are pushed to maximum expansion, then place them around the rear wheel brake disc on the right side.
  6. Push the axle through the wheel by hand or use a rubber mallet to gently nudge the axle through the wheel.
    You may need to give the wheel a wedge underneath to rest on to minimize any stress on the axle while aligning it fully.
  7. Align the right side of the wheel with the swingarm axle hole and brake caliper holder on the right side.
  8. Again, manually push or nudge with a rubber mallet the axle through the speed sensor, rear brake caliper holder, and right swingarm.
  9. Run the belt over the rear sprocket.
    Center the belt over the sprocket so it has about 1mm on either side.
  10. Ensure that all components are aligned correctly before attempting to tighten the axle or even before mating the left axle end with the swingarm (which tightens the belt).
  11. Place the axle nut onto the right side of the axle by hand.
  12. Note the alignment of the left and of the axle's rectangular tabs; hold it in a horizontally aligned position so that tightening the axle nut places it inline with the swingarm slot.
  13. Tighten the axle nut (27mm) with the torque wrench to 75ft-lbs.
    Ensure the alignment of the axle head on the left side is horizontal and pulls the belt under tension smoothly.
    Check belt tension per the belt adjustment procedure.

Rear Bearings

The rear wheel contains 3 bearings and dust shields.

Years Platform Kind Type Code Measurements
2013-2014 S Unsealed 6904-2RS 20x37x9
X 6204 20x47x14
2015-2017 S Sealed NSK 6204DU
X
References
Precision bearings & replacement.
Anyone know front wheel bearing size.
Ceramic bearings for a 2014SR, with success reported.

Rear Bearings Replacement

Rear Wheel - Left Side - Bearing Disassembly.jpg Rear Wheel - Right Side - Bearing Disassembly.jpg

Rear Axle

The rear axle is hollow, threaded on the right side and capped on the left for swingarm fitment.

Axle measurements
Years Inner Diameter Outer Diameter Pitch
2013-2014
2015+ 11mm 20mm 1.25mm

Rear Axle Removal

This is part of Rear Wheel Removal.

Tools
27mm socket
Breaker bar
Instructions
  1. Place the motorcycle on a lift or rear stand so the wheel spins freely.
  2. Mark/photograph where the alignment marks reside on each side of the axle for re-alignment when re-installing the wheel.
  3. Loosen the rear axle nut on the right side (27mm) with the breaker bar.
  4. Remove the rear axle nut.
  5. Pull the axle part-way out so that the wheel can be moved forward enough to loosen the belt.
  6. Pull the belt off of the rear sprocket and let it hang outside of the swingarm slightly to avoid interfering with the wheel.
  7. Pull the axle through the wheel from the left side.

Rear Axle Install

See Rear Wheel Install

Belt

Zero uses a belt for primary transmission of torque to the rear wheel. It's quiet and lightweight but is a proprietary design that can wear out. If you plan to put a lot of miles on a Zero or risk the belt often, buy a spare belt ahead of time and mind its maintenance.

Belt Risks

Belts fail by snapping or by stripping the teeth.

On Landing
The most common situation for a belt snap is when going over a major bump or jump where the rear wheel leaves the ground.
  • If, while airborne, the throttle is not immediately relaxed, the rear wheel will rapidly spin up.
  • A wheel that is moving extremely quickly in the air will get jerked back to its regular speed on landing. This is transmitted to the belt through the rear sprocket and can easily strip teeth.
From Debris
Gravel or sand that gets thrown between sprocket teeth and the belt will force the belt to expand quickly under load, and can cause it to snap.
Reportedly, sand is a much more reliable path to belt failure than gravel.
The sprocket tooth design is meant to deflect gravel to the inside of the swingarm towards the wheel.
The bike has an upper debris guard made of soft ABS plastic, but does not have a lower guard.
From Mis-Alignment
An unaligned belt can wear really badly and break sooner.

Belt Specifications

Zero's final drive is a custom-designed Gates HTD (high torque drive) Poly Chain Carbon toothed carbon fiber belt. It's never been available outside of Zero's parts system. It's been the same part for 2012-2016 models. 2017 models shifted to a wider belt that can accommodate more torque/loading.

Years Width Pitch Models Sprockets Number of Teeth Length OEM Part No.
2012-2016 14mm 8mm S/SR 132T / 28T 220
Previous 30-03673
Current 30-08084 (new logo)
DS/DSR 130T / 28T
2017 17mm 11mm S 13.0 130T / 28T
FX/FXS/DS/DSR/SR/S6.5 90T / 20T
Part
Gates GT Carbon, 14mm wide, 8mm pitch, 220 teeth. It's only available from Zero.
P/N's are 30-03673 ("Belt Drive, 220T, 8mm Pitch, 14mm Wide") and also 30-08084 (same belt w/new Zero logo).
One rough match for reference: Gates 8MGT-1760-12 Belt

Belt Tension Check

Krikit Tension Gauge

Zero recommends the Gates Kritit belt tension gauge to check belt tension.

GATESKRIKITIVBELTTENSIONGAUGE10-04627 invoiceandbox.jpgGATESKRIKITIVBELTTENSIONGAUGE10-04627 gaugeandinstructions.jpg

MostlyBonkers made a How-to video showing how to use it.

  • Turning the back wheel backwards before measuring will give different readout compared to turning the wheel forwards before measuring using the same spot.
    The difference may be significant to the (pre-2017) 20-30kg belt tension specification.
    For wide-belt 2017+ models, the tension specification is very wide (~25-75kg) and thus has a lot of leeway but seems worth a rotational check anyway.
  • The center of the belt can be reached from below, without removing the mudguard.
    This is described as a note in 5.14 in the 2015 manual
More detailed generic instructions for the Kritit deflection device
  1. Ensure the blue indicator arm is pressed down.
  2. Place the gauge in the center of the belt span, such that it is aligned longitudinally with the belt length.
  3. Place a finger on the blue pressure pad and depress this pressure pad.
  4. Keep pressing the blue pressure pad until you feel and hear a distinct 'click'. When this 'click' sound is heard, do not press any further.
  5. Remove the gauge and read the belt tension by observing the point where the top side of the blue indicator arm crosses the numbered scale on the gauge body.
  • Care must be taken to ensure that the gauge is not 'rocked' when pressing down on the blue pressure pad. The strap above the pressure bar is provided to attach snugly over the finger and prevent any 'rocking' motion.
  • Due to the fact that this device requires some amount of practice and operator skill, the accuracy and repeatability of the tension readings are not high.
Improvement

Because this procedure is not trivial to perform consistently, there is a modification to make the tension gauge easier to align

Gates' Carbon Drive mobile app

As of 2017, Zero also includes a procedure in the owner's manuals for using Gates' Carbon Drive mobile app to check belt tension.

Use the application in a quiet environment. Pluck the belt near the center of the lower belt span, so it vibrates like a guitar string.

Recommended Belt Tension
Narrow belt (2013 - 2016 ALL models): 96.3 Hz to 124 Hz, 20 - 30kg
Wide belt (most 2017+ models): 42.5 Hz to 73.6 Hz, 26 - 75kg

The frequency can also be checked with instrument tuning apps such as Tuner-gStrings.

Belt Adjustment

An unaligned or mis-tensioned belt can wear really badly and break sooner.

Alignment Procedure
The official manual has a good procedure from which this is derived. Check that first.
Video instruction: How To Adjust Your Belt on Youtube by Mistasam.
Tools
27mm socket
Breaker bar
Torque wrench set to 75ft/lbs or 102nm
13 mm open-end wrench
Instructions
  1. Place the motorcycle on a lift or rear stand so the wheel spins freely.
  2. Loosen the rear axle nut on the right side (27mm) with the breaker bar.
  3. Loosen both left and right belt tension jam nuts (13mm) that face forward inside the adjusting gap.
  4. Turn both left and right adjustment nuts (13mm) one quarter turn at a time until belt tension reads in specification.
    Ensure that the alignment marks on either side of the swingarm indicate that the wheel and belt are aligned.
    Roll the wheel forward and track it flush with inside of rear sprocket.
    Note: Once tension is set and tracking is flush to the inside, tightening the axle nut to 75ft-lbs will tend to nudge belt approximately 1mm to the outside.
    For proper alignment, the belt will track exactly centered on the wheel sprocket with a 1mm gap to either side of the belt relative to the sprocket.
    Measure tension by rolling the wheel forward while plucking bottom side of belt or using tension gauge several revolutions.
    Note: tension will be expected to vary slightly as wheel is rotated because front and rear sprockets are only round to a certain design tolerance.
  5. Check that the belt is aligned with belt tension in the right range.
  6. Re-tighten the left and right jam nuts (13mm).
  7. Tighten the axle nut (27mm) with the torque wrench (to 75ft-lbs).
Lubricating the belt
A light application of silicone lube to the lower triangle area.
Roll the wheel forward three or four revolutions to disperse lubrication to all areas in contact.
Note: Gates mfg of the belt has not tested this use of lubrication and as a manufacturer, advises explicitly to not do this.
Blast off / super blaster dry silicone lube with orange top.
'Note: Description is hearsay with no specific known lubricating product.

Alignment of the belt is critically tough to get correct, and needs to be done everytime adjusting tension.

References
Belt alignment discussion
How to Adjust Your Zero's Belt
Notes via Shadow

Belt Wear

Generally, watch for belt damage and try to anticipate when to replace the belt to avoid an incident on the road where the belt snaps.

What to Check
  • Check the teeth for wear and cracks.
    If you see cracks in the tooth forming, the belt is getting old.
    If you see deep cracks starting, it's time to replace the belt ASAP.
When to Replace
  • When it snaps.
  • When any teeth have been ground off.
Hard Skips
  • If the belt experiences a "hard skip" from debris between the belt and a sprocket, it is likely to fail soon after. Watch it carefully if this happens.
Tension with aging
Apparently, per forum user JaimeC, belts don't wear like chains.
As they get older they'll actually get tighter, not looser like a chain.
  • When a chain ages, the little bearing points between the links and rollers wear causing the chain to hang looser.
  • When a belt ages, the rubber on the inner/toothed side begins to swell.
Since the Kevlar belt on the outer circumference won't stretch, the inner circumference will shrink making the belt tighter around the sprockets.
Generally, you want to make sure the belt hasn't gotten any tighter since you brought it home.

Belt Replacement

Ask your dealer/Zero before replacing it. They may perform it under warrantee if it happened prematurely; and they'll likely want to understand how and why it broke, anyway, for quality reasons.

Procedure
NOTE: For roadside belt swaps, particularly for an FX or FXS, setting the bike on its side should be possible for this work.
However, no effective procedure has been described for the process.
The following steps are suited to garage locations.
  1. Lift bike with a center stand. A wood crate will work.
    Onlift.jpeg
  2. Pull the wheel off (or slide it forward) by loosening the axle nut with a 27mm wrench.
  3. Pull off the rear tire fender by taking out the 4 hex bolts securing it with a 3mm Allen wrench.
  4. Remove the right side rear brake lever (15mm bolt).
    Rearbrakebolt.jpeg
  5. Remove the left and right swingarm bolts.
    2012-2013
    Remove the set screws from the swingarm bolts on both sides with a 2.5mm Allen wrench, then remove the bolts by holding the inside nut with a 24mm wrench, and a 10mm hex on the head.
    This was the hardest step, because there is not a lot of room to manipulate in the rear assembly - especially with a 24mm wrench!
    2014+
    Remove the left and right swing arm bolts with a 10mm Allen wrench.
    Swingarmbolt.jpeg
  6. Hang the swing arm with a strap on the tail section.
  7. The swingarm will pull back enough for the belt to fit through the frame. Simply slide it over the motor pulley, replace the swingarm bolts, then install it over the rear wheel and tension accordingly.
    Swingarmpull.jpeg
    Swingarmpulled.jpeg
  8. Put it all back together

Adapted from Discussion for a 2013 S, DoctorBass and Facebook comments by Bobby Loo.

Sprocket

Sprocket Specifications
Belt Front Rear
Years Width Pitch Models Teeth Depth Teeth Depth
2012-2016 14mm 8mm S/SR 132 1" 28
DS/DSR 130 28
2017 17mm 11mm S 13.0 130 28
FX/FXS/DS/DSR/SR/S6.5 90 20
Reference
2013 DS chain drive

Sprocket Wear On Belt

Wear debris from the tire or the road can accumulate on sprocket teeth, putting pressure on the belt which can wear it out faster.

Recommendation
Keep the sprocket teeth clean to minimize wear on the belt.
A non-abrasive brush should be effective.

Front Sprocket Removal / Swap

Some guidance from Terry in this motor removal thread:
  • Basically, if you are doing this to try to get more acceleration by moving from a 28 tooth to a 25 tooth, Harlan recommends trading in the DS on a 2015+ SR or 2016 DSR if you need the off road capabilities. You will get much much more acceleration and not hurt your top end performance.
  • On the drive belt side, the upper rear 5mm bolt takes extreme care to remove. It is tapered to locate the motor. There is a very strong chance of stripping the head and have to drill it out. Make sure to have a machine shop close by just in case.
  • The other 7 bolts, 3 on the sprocket side and 4 on the rear brake side are the only thing simple and straight forward.
    You will need a special 3" or longer 6mm allen head socket for sticking in the hole through the frame at the front of the motor.
    1. Remove the rear brake pedal and assembly to get the heel guard out of the way of the top right rear motor bolt.
      Be careful not to strip these bolts either.
      They have Loctite; use a torch.
      And make sure your local hardware store has these replacement bolts handy in case you have to drill them out.
      The rear brake pedal needs to move anyway to get the right swingarm bolt out.
  • Also the sprocket bolt itself, as well as removing and installing the new sprocket on the shaft can be very difficult. Some of the best professionals have had trouble.
    Loctite has been used on everything and you will need a torch to remove them.
    Even so, you will need a strap wrench with an old belt as the strap to hold the sprocket and a high power impact wrench.
  • Even with all that right, you have a chance of stripping or breaking the bolt. The sprocket is pressed pretty tight.
  • Be very careful not to permanently damage the motor bearings by prying between the motor itself and the sprocket to try to remove it, and also by tapping with a hammer to try to fit the new one on. You will be tempted to do both, but you need to find another way.
    A gear puller would be much better.
  • There are other things to watch for:
    • Mark your phase leads and pay special attention to the routing.
    • Don't over-tighten the motor jack nuts and bolts until you have the swingarm back in place as it can pull the frame together slightly making it impossible to get the swingarm in place.
    • Make sure you unplug the 8 way motor encoder harness and it doesn't get yanked and pull a wire.
    • The top shock mounting bolt is a 15 and 17 mm and can be done with ratchet wrenches 1/32 of a turn at a time, or without ratchet wrenches if you are known to have extreme patience. It can take a while. The 2014 is a little easier and is (seems to be a) dual 17mm bolt and nut.
    • The swingarm bolts are 10mm allen head and can be extremely hard to relocate even when working with someone else, a rubber hammer, and a flashlight. Those who have replaced their own belt before can vouch for this.
  • Again, I doubt too many on this forum have done this, and those who did I'll bet agree with me that it makes more sense after they did it and perhaps had their bike out of commission to work through the things that didn't go right, and would agree to just upgrade to the SR or DSR first vs trying to change the front sprocket.
  • Also the 25 tooth sprocket will break belts easier as less teeth are engaged than the 28 tooth, which can make it more likely to sheer teeth in the event of a wheelspin, and it bends the belt at a sharper radius which can possibly fatigue the carbon strands more. The SR actually uses a 30 tooth front sprocket which is even nicer to the belt than the 28 tooth.

Brakes

Zero motorcycles so far have had single-disc brakes for front and rear systems.

It is only a question of time when Zero will add double front disk brakes in the road bikes range. Single disk is not recommended for the kind of speeds/overall weight the new models are reaching.

General Maintenance
Check for pad wear or debris; keep the pads and discs clean. An occasional brushing of the disc holes is worth doing maybe once a year.
Check hydraulic fluid level.
Make sure the brake fluid is in good shape and the type/specs you need, if in doubt replace with fresh fluid (not from an already opened bottle).
Make sure the brake fluid reservoir over-filled (top), there has to be some empty space, or your bike will be lightly "braked" and your disk/pads will deteriorate prematurely...and you will get less range.

Another suggestion is to remove the rear brake spring or replace it with a lighter spring. On most models, there is a spring suitable for a dirt bike that is over-designed for a street bike. There is a kind of spring inside the brake pump, so the external one is just to keep the foot-pedal without rattling. Test the rear brake after doing this.

Brake Systems
Year Front Rear Notes
2013 Nissin Nissin relatively weak

J Juan upgrade available for rear brake.

2014 J Juan Same pad sizes as 2013.
2015 J Juan Bosch Gen 9 ABS; New pad sizes.
2016 Bosch Gen 9 ABS
2017

Brake Hydraulics

Models Front
Platform Years Caliper Piston Area MC Piston Area Hydraulic-Advantage Ratio
S 2015 1509 mm² (total) 126 mm² 11.9:1
2016
2017
Regarding Brake Upgrades:
A 9.5mm-piston master cylinder - like the Nissin 3/8 I put on my 'MX' bike - would give the SR a 21.1:1 ratio, or @ 78% more pad pressure than the OEM 12.7mm master cylinder.
Any Brembo, Nissin, etc. 9.5mm / .375" master cylinder w/switch should drop right in and make a huge difference, and you won't have to touch anything else.
On the rear, the 11mm master cylinder from the FX (Zero part# 25-06731) has 49mm M6 bolt spacing / rear reservoir hose / top output / clevis, and should give @ 19% more pad pressure than the SR 12mm master cylinder.
This won't be a night-and-day difference like the front master cylinder change, but it should still be very noticeable.

Brake Pads

General Reading Material
Top 10 Questions About Motorcycle Brake Pads
Motorcycle Brake Pads & Rotors Explained, by Galfer USA
General Brake Pad Replacement Suggestions
Try to not use synthetics pads or "sintered", but organic or semi sintered ones.
Sintered are better for very aggressive riding/braking, but are generally noisier.
Sand the pads.
In the 2012 models, keep the sintered pads; the brake pump is very weak.
Grease the back of the pads lightly with copper grease.
Check caliper position.
Check caliper springs, if any.
Check the wheel for trueness.
Sand the disk; it could have lightly crystalized.
Make sure all the bolts in the system (including wheel) are properly tightened.
After all of this has been preformed and before riding, clean everything exposed to dirt/grease with isopropyl alcohol
When riding again, try to not brake very aggressively the firsts 20-30 miles.

Brake Problems

Squeak
Brake squeak (pad front against the disc) happens occasionally and is relatively quiet and noticeable but not anomalous.
Squeal
Brake squeal (pad back resonating against caliper cylinder) can be very loud and annoying. Squeal does not technically impact performance but it's very unpleasant and might cause the rider to hesitate before fully braking which is a safety issue.
Solutions
  • Clean the pads and/or discs for squeaking.
  • Try a different brake pad (attractive if you want a different pad feel or performance in the first place).
  • LocTite Disc Brake Quiet stick applicator for the backs of the pads.
  • Chamfer the brake pads
    File the edges of the pad to put a 45 degree edge on them
    You only need 1-2mm

Brake Pad Fit

Nissin (2013 on rear, and 2013/2014 front)
J Juan (2014+ on rear, 2015+ on front)
Front pad shape FDB892
Rear pad shape FDB539

Past forum threads of highly varying quality / ability to clarify:

EBC
The EBC brake catalog covers Zero models.
However, it has always had the wrong shape recommendation for 2013-2014 models, and for the FX entirely! Double-check any recommendation.
SBS
offers a brake search engine which covers Zero models.
Goldfren
offers a good cross reference between brands.
Brembo
Brembo's Motorcycle Brakes Configurator has reasonably usable Zero model lookup.
Their Carbon Ceramic pads are reported to resolve brake squeal issues.
Stock and Replacement Pad Specs (needs refinement/checking)
Front Rear
Year Models Stock SBS EBC Brembo Galfer Stock SBS EBC Brembo Galfer
2010-2012 S/DS SFA264 708 HF FA264 N/A 188 544 HF FA83 07KA07 094
X/XU/MX
2013 S/DS/FX/MX/XU Nissin TT2508HH sintered-metal 694 HS FA185 07KA17 164 Nissin TT2182FF 790 LS FA367 07YA41 286
2014 S/DS/SR 675 HS FA208,FA213 07BB02 165
FX Galfer FD093 G1651 semi-metallic 604 FA131 147
2015-2017 S/DS/SR/DSR 674 HS FA209 07BB03 172 675 HS FA208,FA213 07BB02 165
FX/FXS 671, 742 FA181 138
References
Honda / Nissin front brake shoes; goodbye screech, hello stoppies
2015 FX Brake Pads?
Brake pads for 2014 SR
Brake pads for 2015 FX, 2016 FXS

Brake Pad Replacement

Rear Pad Replacement for J Juan rear brakes (2014+)
Tools
  • #25 Torx bit screwdriver
    Torx t25.jpg
  • Flathead screwdriver
  • Small pliers
  • 200 grit sand paper (optional)

Rearbrakes jjuan.jpg

  1. Remove safety spring-clip from the rear of the bolt (on the side of the wheel).
    Just push it out with a flathead screwdriver.
    Rearbrakeclip.jpg
  2. Remove the bolt that goes through the "eye" of the brake pads (using #25 torx driver).
    Rearbrakebolt.jpg
  3. Pull out the pads.
    They just come out when pulled gently by hand towards the rear of the bike.
    Rearbrakepads jjuan1.jpg
  4. If there's any debris like paint on the pad material, you may want to sand them flat/clean gently over some 200 grit sandpaper on a flat surface.
  5. Put in new pads.
  6. Screw-in the bolt.
    It maybe good to use some anti-seize paste if not present from the factory.
    Torque value unknown, but be quite gentle - probably something like 10lb/ft (hand-tighten firmly with a regular screwdriver kind of torque).
  7. Reinstall safety clip.
  8. Test your ride carefully!

Powertrain

Motor

All of Zero's motors are air-cooled and mounted on a shaft that is aligned with the front pivot of the swingarm so that transmission tension is perfectly aligned with swingarm movement.

Motors by Model
Brand Designation Years Models
Agni/Saietta 95-R alt 2009-2012 S/DS/X/MX
Z-Force 75-5 2013 FX/MX/XU
2014-2015 FX
2016 FX/FXS
75-5 (IPM) 2017 FX/FXS/S ZF6.5/DS ZF6.5
75-7 2013-2016 S/DS/MMX
75-7 (IPM) 2017 S/DS/MMX
75-7R 2014-2015 SR
75-7R (IPM) 2016-2017 SR/DSR

Agni Motor

From 2009 to 2012, Zero used brushed DC Agni/Saietta 95-R motors.
These have known quality issues after time and Zero offers many owners a Z-Force motor upgrade or complete trade-in for remaining 2014 models.
2012 to 2013 motor upgrade info

Z-Force Motor

For the 2013+ models, Zero has their own motor design, trademarked "Z-Force" built by Motenergy (they make similar generic models).
Zero uses Sevcon Gen4 size 4 controllers for the base Z-Force models.
It is a sealed, air-cooled 3-phase brushless motor with inbuilt speed sensors which is roughly described as brushless DC (BLDC) or permanent magnet AC synchronous (PMAC) since the controller is continuously adjusting the phase angle of the field to the rotor's current position and speed.
The X platform uses the 75-5 model.
The S platform uses the 75-7 model.
Motor theory
IPM vs SPM for a different motor control regime but some principles translate to the Z-Force motor.
Efficiency
forum thread
Range vs Speed by Patrick Truchon discusses the theory and measurements in depth.
Does Gear Size Affect Range? by Patrick Truchon with more theory!

Z-Force Motor R-Variant

The 75-7R motor was introduced in 2014 with high-temperature magnets.

These require Sevcon Gen4 size 6 controllers to deliver more current and torque
SR (2014+) and DSR (2016+) models use these motors.

Z-Force Motor IPM Update

In 2016, Zero introduced an interior permanent magnet (IPM) design as distinguished from a surface permanent magnet (SPM) design of the original motor introduced in 2013.

The IPM design reduces the heating associated with developing magnetic flux and distributes the heat produced more evenly.
This allows the motor to operate at higher outputs while producing less heat overall and concentrating heat production where it dissipates more easily.
In practice, this avoids hitting thermal limits which require cutbacks to protect the motor windings.
2016 models S/DS/SR/DSR/FXS have the IPM design.
FX and S/DS models with a 3-brick battery retained the SPM design (presumably to be phased out with inventory).
Zero livestream announcing 2016 upgrades
Zero livestream presentation with Ryan Biffard about the Z-Force motor IPM upgrade
The IPM design motor apparently involves custom Zero programming of the Sevcon controller for the encoder, so off the shelf DVT software cannot perform alignment/commissioning but can apply settings / DCF files and restore them.

Z-Force Motor Mount/Torque Update

In 2017, the Sevcon controllers were updated ("4.5" is the unofficial revision) to support more current to the motor.

The belt was also reinforced and widened to apply more torque through the transmission and be more robust against interference.
Accordingly, the motor shaft is now splined instead of keyed so the motors and sprockets are not compatible across the 2016-2017 year-line.

Motor Mounting

Burton's 2013 to 2014 motor swap thread shows the most detail about the physical mounting of the motor.

Motor Shaft

Pre-2017
The motor shaft is keyed.
2013 models had a minor recall about the shaft key coming loose, but this was a design revision that has not recurred.
2017+
The motor shaft is splined to allow higher torque transmission.

Motor Sounds

When the contactor is closed and the controller is engaged, if you push the motorcycle around without it being under power, you'll hear a soft whirring sound.
This sound is from the controller applying a field to the motor trying to track its position to prevent cogging.
Cogging is a term for the rotor moving out of sync with the stator magnetic field and this is related.
This is normal and harmless on a Zero.
This sound is a confirmation that the contactor is shut and that the motorcycle should be ready to drive (aside from kickstand and motor cutout interlocks).

Motor Wiring

The motor's stator is connected to the controller for power and position feedback.

  • 3-phase power inputs from the controller.
  • Motor position sensor (again to the controller).

Motor Alignment

The back side of the motor (encoder side) has screw jack bolts that let you tweak the motor position. Mostly this is only needed when (re)installing the motor.

Procedure
  1. Loosen the four M6 socket head screws.
  2. Adjust the portion of the silver nut that is not wedged into the slot on the motor.

Motor Commissioning

Motor commissioning refers to aligning the controller's sine wave programming against the motor using its position sensors.

Benefits
Maximum efficiency (avoids current applied wastefully)
Avoid any slippage.
Avoid misapplied torque which might wear on the bearings.

Controller

This encodes three-phase sine waves from the DC power and a number of signals.

The power is applied to the motor in synchronization with the current speed and position of the rotor.
Controller alignment (motor commissioning) is the process of tuning all of this for maximum efficiency and to avoid any slippage.
Years Models Controller Type Current Rating
2013-2016 S/DS/FX/FXS/MMX Sevcon Gen4 Size 4 420A
SR/DSR Sevcon Gen4 Size 6 660A
2017+ S/DS/FX/FXS/MMX Sevcon Gen4.5 Size 4 550A
SR/DSR Sevcon Gen4.5 Size 6 775A
2017 "Gen4.5"
2017 models reference higher current ratings without publicized evidence of a Sevcon model change.
These improvements seem to be in choosing MOSFETs with increased power switching efficiencies to allow higher continuous and peak current levels.
"Gen4.5" has been a term heard describing these improvements.

Controller Feature Usage

Throttle
Sevcon provides the throttle with two mappings:
  1. Mapping voltage to value in the first place (separately for forward and reverse)
  2. An "input characteristic" profile which has linear, curved, crawl, and user-defined segmented options.
The controller also supports:
  • Control modes targeting speed (used through 2012) versus torque (used in 2013+).
    The control mode translates the throttle signal into motor operation, so it makes the throttle target a speed or a level of torque.
  • Dual throttle inputs.
  • Regen proportional to the throttle.
  • Directional throttle.
  • Speed limit proportional to throttle.
  • Reverse speed limit.
Regen
The Sevcon controller manual refers to regen as braking, and has a number of recommendations and features disabled to help prevent wheel lockup for "on-highway applications".

Zero programs the Sevcon controller for their specification; some of this is a bunch of settings and some of this seems to be a custom version of the firmware code; the new IPM motor may have demanded further customization than previous models. Settings can be changed and restored, but not code without some OEM-supported technical assistance.

Controller CAN Diagnostics

Emergency (EMCY) codes from the Sevcon Gen4 drives

CAN message examples
ID    b0 b1 b2 b3 b4 b5 b6 b7
"81";"00 31 04 C3 4D 00 00 00"
"81";"00 31 14 C3 4D 00 00 00"
"81";"00 82 10 0F 53 02 00 00"
"82";"00 10 01 54 4F 00 40 00"
"82";"00 10 11 54 4F 00 40 00"
"82";"00 31 04 C2 51 00 00 00"
"82";"00 31 04 C2 51 00 04 00"
"82";"00 31 04 C3 4D 00 00 00"
"82";"00 31 05 C3 4D 00 00 00"
"82";"00 31 15 C3 4D 00 00 00"
"82";"30 81 10 0B 53 01 00 00"
Bytes b1+b0 (switch bytes)
Bytes b1+b0 (switch bytes) describes CanOpen error code according to DS-301
Error code (hex) Error description
00xx Error Reset / No Error
10xx Generic Error
2xxx Current
3xxx Voltage
4xxx Temperature
50xx Device Hardware
6xxx Device Software
70xx Additional Modules
8xxx Monitoring
90xx External Error
F0xx Additional Functions
FFxx Device Specific
Byte b2
Byte b2 is error register, bit-wise coding, also according to DS-301
Bit Error cause
0 Generic Error
1 Current
2 Voltage
3 Temperature
4 Communication Error
5 Device Profile Specific
6 Reserved (always 0)
7 Manufacturer Specific
Bytes b5-b7
If any of bytes b5-b7 are not 0x00 means error is set.
If bytes b5-b7 are all 00 it means the error is reset.
Might be only b6?
Bytes b4+b3 (switched bytes)
Bytes b4+b3 (switched bytes) describes Sevcon specific errors
Code Interpretation
0x2401 Login
0x3441 Host SW Upgrade
0x3442 DSP SW Upgrade
0x34C1 Watchdog Reset
0x45C1 BDI Warning
0x45C2 BDI Cutout
0x45C3 Low battery
0x45C3 Low battery
0x45C4 High battery
0x45C5 High capacitor
0x45C5 High capacitor
0x45C6 Vbat below rated min
0x45C6 Vbat below rated min
0x45C7 Vbat above rated max
0x45C8 Vcap above rated max
0x45C8 Vcap above rated max
0x45C9 Motor low voltage
0x45CA Motor high voltage
0x4601 Device too cold
0x4602 Device too hot
0x4603 Motor in thermal c/b
0x4603 Motor in thermal c/b
0x4681 Preop
0x4781 Anon EMCY
0x47C1 Service Required
0x4881 Seat
0x4882 Two Dir Fault
0x4883 SRO Fault
0x4884 Sequence Fault
0x4884 Sequence Fault
0x4885 FS1 Recycle Fault
0x4941 Low oil
0x4981 Throttle Fault
0x4981 Throttle Fault
0x4B81 Anon EMCY
0x4C41 Too Many Slaves
0x4dC3 Supply Critical
0x4F01 Bad State
0x4F02 EMCY Fail
0x4F41 Internal Fault
0x4F41 Internal Fault
0x4F42 Out of Memory
0x4F43 General DSP Error
0x4F44 Timer Error
0x4F45 Queue Error
0x4F46 Sched Error
0x4F47 DSP Heartbeat
0x4F48 IO SS Error
0x4F49 GIO SS Error
0x4F4A LCM SS Error
0x4F4B LCP SS Error
0x4F4C OBD SS Error
0x4F4D VEHAPP SS Error
0x4F4E DMC SS Error
0x4F4F TracApp SS Error
0x4F50 New PF Detected
0x4F51 DSP not detected
0x4F52 DSP Comms Error
0x4F53 App Mgr SS Error
0x4F55 DSP param
0x4F81 Anon EMCY
0x5041 Bad NVM Data
0x5042 VPDO out of range
0x5043 Param fixed range error
0x5043 Param fixed range error
0x5044 Param dyn range error
0x5044 Param dyn range error
0x5081 Invalid Steer Switches
0x5101 Line Contactor o/c
0x5141 Line Contactor welded
0x5181 Dig In Wire Off
0x5182 Alg In Wire Off
0x5183 Alg Out Over I
0x5184 Alg Out On with No FS
0x5185 Alg Out Off with FS
0x51C1 Power Supply Interrupt
0x51C2 Precharge fail
0x52C1 Encoder fault
0x52C3 Current Control Fault
0x5301 CANbus Fault
0x5302 No Bootup
0x5303 LPRX CAN
0x5304 LPTX CAN
0x5305 HPRX CAN
0x5306 HPTX CAN
0x5307 CAN Overrun
0x5308 CAN Off
0x5309 Nodeguard Error
0x530A PDO Short
0x530B HBeat Error
0x530C CANopen Device State
0x530D CAN Error State
0x530E SDO Handle Error
0x530F SDO Timeout
0x5310 SDO Abort
0x5311 SDO State Error
0x5312 SDO Toggle Error
0x5313 SDO Rx Error
0x5314 SDO Length Error
0x5315 SDO Tx Error
0x5316 CANopen Ev Unknown
0x5317 SDO Bad Source
0x5318 SDO Bad Error No
0x5319 Mtr Slv in Wrong State
0x5319 Mtr Slv in Wrong State
0x5341 Wrong DSP protocol
0x5342 Osc WDog Tripped
0x5343 Flt o/flow
0x5381 Anon EMCY
0x54C1 DSP Overvoltage
0x54C1 DSP Overvoltage
0x54C2 DSP PF Fault
0x54C3 Mosfet s/c M1 Top
0x54C4 Mosfet s/c M1 Bottom
0x54C5 Mosfet s/c M2 Top
0x54C6 Mosfet s/c M2 Bottom
0x54C7 Mosfet s/c M3 Top
0x54C8 Mosfet s/c M3 Bottom
0x54C9 Mosfet tests incomplete
0x5741 Invalid Rating
0x5781 Anon EMCY
Example
ID    b0 b1 b2 b3 b4 b5 b6 b7
"82";"00 31 04 C2 51 00 04 00"
Node id 2 sends emergency error.
Error code: 0x3100 (b1+b0) meaning "Voltage" error category
Error cause: 0x04 (b2) bit 2 set meaning "Voltage" error cause
Sevcon error: 0x51C2 meaning "Precharge fail"

Controller Configuration

The controller's configuration implements a number of Zero features:

  • Speed calculations.
  • Distance calculations.
  • Over-voltage limits to protect the battery by cutting out regen or refusing to operate.
  • Under-voltage limits to protect the battery charge state.
  • Current limits to protect the battery.
  • Delay before regen toggles on or off.
  • Driving modes like Eco/Custom/Sport which include speed and torque limits and speed ramping limits to prevent wheel lockup.
References
Sevcon Gen4 product page
Gen4 data sheet
Gen4 reference Manual
Location
Beneath the seat at the front of the tail assembly, under a plastic sheet cover.
Mounted from the underside of the tail of the frame, between the frame "horns", with a set of fins for radiative cooling.
4 bolts secure the controller to the frame (need to confirm sizing and whether/how this varies for size 4 and size 6 controllers).
Accessing
  1. Key off the motorcycle, and confirm that the contactors open.
  2. Wait 10 minutes to ensure any residual voltage between the battery and controller has dissipated.
  3. Uncover the controller by using a Philips head screwdriver to loosen the screw retaining the plastic sheet covering the controller.
Connectors
Main terminals are, in order from front to rear: M1, B-, M2, B+, M3. The bolts are all M8 with a torque setting of 11Nm±2Nm; bolts should engage a minimum of 10mm and thread depth is 15mm.
M-terminals supply the motor with its rotating field in three phases. Each gets a sine wave that is offset by 0, 120, 240 degrees.
B+ and B- connect to the battery power at positive and negative, respectively.
Connector info (see AMPSEAL Automotive Plug Connector and Header Assembly (PDF, English))
More connector info (look at bottom for pins)
Configuration
Some MBB settings direct the Sevcon controller; look to the MBB first.
The MBB can also provide a dump of Sevcon diagnostics and logs.
DVT software to maintain the Sevcon programming is available but recent versions require a license and the cabling is not cheap. The older unlicensed versions may have trouble maintaining newer programming by Zero.
Direct diagnostics
For those interested in better understanding your Zero's motor controller setup, you'll need some specific cables and software. These will allow you to browse the current controller configuration as well as make changes such as increasing regeneration rates, customising sport or eco modes etc.
This is what you'll need:
  1. An IXXAT CAN-USB compact adaptor v1.5 (v1.01.0087.10100) or v1.6 - approx USD300 but you may find it cheaper on eBay or borrow/rent it from another forum member or dealer.
You cannot buy these anymore, you must get them off ebay or part of a Thunderstruck EV $900 kit.
You cannot use a new version of the IXXAT CAN-USB either as it will not work with an unlicensed copy of the software. And to get a license you have to own a business.
  1. A DB2 female to OBDII male cable with a specific pin mapping (not the most common one). Easysync make a DB9 female to OBD male cable that has the correct pin configuration - about USD25
  2. Sevcon DVT Customer software
It has to be version 1.03c or lower to use unlicensed (Google is your friend, as is Dropbox in this case).
Good luck saving your DCF files with it. You need to write down your settings before making big changes. Even if you bought the new version and got a license you would have to use a NEW IXXAT USB-CAN as the old one isn't compatible.
The Sevcon software will run on Windows XP, 7 and 8. There are manuals and getting started guides on the Internet (Google again) on how to use the DVT software including one at Thunderstruck EV.
WARNINGS
Do not link any files as they have been removed multiple times in the past. One of the dropbox links you will find will have at least 3 different versions. If you install any new versions completely remove everything from the previous versions. If you find the program wont start up and it isn't 1.02 then install a "merge" installation of TCL and it should work.
You can brick your controller temporarily by making changes. It would be nice to have a backup but these online versions of "free" sevcon software all have issues with saving. I have tested 1.00 1.01 1.02 (which never ran) and 1.03c so far. If you brick your device you will need someone to give you a DCF file to return your device to working order. But good luck getting it from a form member who doesn't work for a dealer as stated it is next to impossible to export the file.
Sevcon is very much against this use of their product and software, and have issued takedown notices for publicly available files.
You will not get official support and people will be reluctant to post details publicly. Get the 200 page DVT / SEVCON GEN 4 manual from the manufacture's webpage and read it a couple times. Try contacting knowledgeable people privately.
You really need to understand what you are doing when you start to make changes. This isn't a toy you are going to be remotely piloting, it is a vehicle you are risking your life on!
Zero has specific programming to customize the Sevcon controller, so it is not clear whether customer customization is achievable beyond basic modification of settings or performing an alignment using DVT.
Recovery
DoctorBass has documented a backdoor method of recovering a Sevcon controller if its firmware is in an unusable state
Using the IXXAT connection, issue the following command:
can send "0x7FA 0x48 0x65 0x79 0x73 0x6c 0x69 0x70"
This byte sequence is also apparently available as "BD" (for "backdoor", presumably).

Systems

Instrument Cluster

Until 2014, Zero used branded versions of generic Koso instrument clusters, mapping the fuel level indicator to battery state of charge.

Pre-2014
The 2012-2013 RX-1N shows battery level in 11 increments.
It's relatively effective to treat each increment as representing 9% of charge state, and do a little mental math to figure out that each increment could represent 5-10 miles (for say 2013), and work out the remaining range / speed tradeoff from that.
  • go slower to get closer to 10 miles of range per increment
  • go faster if you can afford to burn off the battery to reach your destination in time.
The Koso instructions linked below show how to operate it.
2014+
The 2014 custom gauge changed the pin connector, so there's no simple way to install one on an older model.
It offers an ergonomic advantage that the instrument cluster no longer obstructs access to the keyed ignition and steering lock.
The state of charge reading is now primarily numeric as a two-digit percentage, with a continuous bar level reading next to it.
  • Disadvantage: no countable number of increments and also making the rider more aware of state of charge calculation nuances.
  • Advantage: It's more accurate, and the dash's other functionality (like range and efficiency readouts) easily compensates for remaining inaccuracies.
The OEM manual explains its capabilities pretty well.
Instrument Cluster
Years Manufacturer/Product Reference
2008-2011 Koso XR-SR Instructions
2012-2013 Koso RX-1N Instructions
2014-2017 Zero custom Owner's manual
Common Problems
Mostly these have issues due to moisture entering the (relatively well-sealed) housing.
This can be disassembled for cleaning but would need re-potting with dielectric grease perhaps when re-assembling and need to be very clean and try inside.
Diagnostics
See MBB Console Dash command

Throttle

The Zero throttle is a very straightforward twist-grip motorcycle control that operates a linear potentiometer instead of pulling on a mechanical cable or operating hydraulics.

Zero switched the throttle supplier from Magura to Bitron in 2015 which changed how the wiring works.

Customization
See Unofficial_Service_Manual#Drive_Modes Drive modes to customize throttle input interpretation as an owner.
Use the mode control for "Custom" mode on 2014+ or "Eco" on earlier models to set the maximum torque the throttle applies.
This also directly changes how quickly torque ramps up for a given throttle twist/position.
Advanced Customization
The Sevcon motor controller settings are where most of the throttle interpretation happens.
Replacement
TODO...
Assembly
The return spring cannot be tensioned while disassembled throttle is on the handlebar. Throttle must be removed to place the spring end correctly. see video from Harlan Flagg: https://www.facebook.com/harlanflagg/videos/1364143910276196/
Troubleshooting
One report of a "snatchy" throttle turned out to have this explanation:
There is a black adjusting screw which holds the pinion gear of the throttle in place or for adjustment.
The pinion gear had moved to the right and caused the spring clip for throttle return to pop out of the slot.
This was clicking through the gears and causing a notchy throttle feel.
Resolution: Reset the pinion location and tighten the screw.

Magura Throttle

The 2012-2014 stock throttle is a 5kOhm Magura throttle

Basic details
The Magura Twist Throttle has a 0-5k ohm output.
Comes with matching grip for opposite side.
7/8" (22mm) handle bar fit
68" long control cable
Weight: 0.5 lbs
Connectors
Three wire output.
Blue Wire = Throttle High
Brown Wire = Wiper
Black Wire = Throttle Low

The signal is sent to the MBB, and then to the Sevcon motor controller.

Bitron Throttle

2015+ models use a new HAL-based (Hall-effect active device) sensor from Bitron which can't be replaced easily by Domino or similar

Product reference: Bitron HAL-based throttle
Connectors
Via Keith's investigation
8 wire output, bundled into two pairs of 3 wires for potentiometer outputs.
Throttle-wiring-bitron.png
Sumitomo connector 6188-0779
Sumitomo connector 6189-1240
The hall-effect sensor may be a potentiometer wired up as a voltage divider as follows:
Measured voltages
Wire Twist Voltage
Brown None 0.5
Full 4.5
Brown/Red None 4.5
Full 0.5

Regen

The Sevcon controller can enter a regeneration mode where it captures momentum from the motor and charges the battery.

Operating Range
Regen for Zeros operates between 12mph (where the motor cannot produce enough voltage to naturally power through the controller) and 4500 RPM (70mph in default gearing).
This band can be adjusted in MBB settings.
Level
Regen levels are defined/set in terms of percentage of maximum allowable levels, so 0-100%.
That 100% maps to a 40A recharge limit setting in the Sevcon controller, equivalent to 10% of the maximum discharge rate of a Gen4 size 4 controller.
The 100% setting also corresponds to 60% of the 72Nm torque limit also specified.
The recharge limit may be set up to 91A via Sevcon setting or higher by a dummy value (65535?).
Zero sets regen levels to preclude rear wheel lockup, so raising the limit is a risk that ABS cannot directly control.
Regen has the same effect for SR/DSR models as for S/DS.
Efficiency
The recharge efficiency of regen is typically that 10% of the energy used to climb an incline can be returned on the corresponding descent.
Triggers
  • Normal regen is triggered by relaxing the throttle.
    There is a position just above the resting position where an actual neutral torque is achievable.
    The MBB has a setting in mV for the potentiometer output of the throttle to trigger regen.
    Adjusting this is not normally effective unless changing throttle types.
  • Brake regen is triggered by the same signal that turns on the brake light:
    A contact switch against the front brake lever will engage the brake light (and regen); the hydraulic piston and the switch engage simultaneously by default.
    Rear brakes engage pad contact and the brake light (and regen) simultaneously, but require some amount of travel before they engage.

Drive Modes

2009-2013
  • Through 2013, only Eco and Sport modes were available, where Eco was the customizable mode but had the Eco default as listed below.
  • The modes are selected with a rocker switch on the left part of the steering head bracket forward from the handlebars.
2014-
  • 2014 models introduced a separate Custom mode and made Eco mode fixed.
  • Modes are selected by pressing a selector button on the right hand switch assembly; the selected mode then activates when the throttle is released for a couple of seconds.
Default mode settings
Mode Max Speed Max Torque Max Regen Max Regen Brake
Eco 70 mph 40% 66% 100%
Custom 70 mph 100% 40% 66%
Sport 98 mph 100% 40%? 66%?

Charger

Zero motorcycles have a stock Level 1 charger built in.

Location
Bolted onto the underside of frame under the battery pack.
Protected by a metal belly pan on the DS/DSR/FX and very hard ABS plastic on the S/SR/FXS.
Inlet
S Models - Located on the left side of the frame above the footpeg with a rubber boot attached.
X Models - Located in the front below the right "batwing".
The inlet is an IEC 60320 C13.
Connections
Charger electrical connections face the rear towards the motor; cables run upward.
Power
The onboard charger for Zero motorcycles is rated to use 100V to 240V AC but is limited in capacity to the 110V power rating, so operates at half current at 220V.
Efficiency should be a little bit higher at higher voltages because of the reduction in current.
Onboard Charger Models
Platform Years Charger Power
S and X 2009-2012 1x DeltaQ QuiQ 1000 1000W
S 2013 4x Mean Well HLG320H-54A power supplies emitting 320W each in 2 parallel series of 2. 1300W
2014-2017 1x GreenWattPower (Calex subsidiary) Calex EVC-116-1200
X 2013-2014 2x Mean Well HLG-320H power supplies in one series. 650W
2015-2017 1x GreenWattPower (Calex subsidiary) Calex 720 Watt EVC 720W
Reliability
Certain model years (MY14 and MY15) have had onboard charger faults after 900-1200 miles and require replacement under warrantee.
MY16 and MY13 appear to have a lower defect rate.
This appears to be a third-party quality issue with Calex that was reportedly resolved by early 2016, but this is not proven perfectly yet.
Maintenance Recommendations
To minimize risk of a charger fault or component burnout, check the Common Charging Problems section.
Basic suggestions:
  • Keep the inlet covered when not in use.
  • Use contact cleaner on the inlet periodically (once per month) or whenever the charging cord plug warms up significantly during charging.
  • Minimize strain and load on the charging cord.
  • Unplug the cord and cover the inlet when not in use.
GFCI
Ground fault circuit isolation (GFCI or GFI) enabled outlets often trip when using the Zero onboard charger, relating to how AC phases are wired to a single or multiple outlets.
If this happens regularly, it is reasonable to break off the grounding pin from your charging cord, or, better yet, get a cheater (three prong to two prong) "cheater" plug.
Cord
The charging cord is a 20-ft 14AWG cord with a NEMA 5-15P (US) to IEC320 C13 output plug rated for 15A; the onboard charger draws 11-12A at 120V AC (and half the amps at ~220V).
Zero specifies that any extension cord be at least the above specification, and 15A continuous rating is important to look for. When in doubt, prefer a thicker gauge cord, a shorter length, and a sturdier plug.
Do not let a charge cord sit coiled up, particularly in a container; make sure that any heat produced is not confined near the cord for any reason.
Plugging into a 220V outlet will reduce the current to the onboard charger by half, so is one way to drastically minimize risk to any cords.
Behavior
Per CANBUS diagnostic reply, the Calex charger reports its basic settings:
  • Maximum allowed battery voltage: 116.4V
    Tapering starts when battery voltage reaches or exceeds this value.
    Tapering behavior is observed to reduce output current in increments of 1A and typically starts at 12A.
  • Current taper cutoff: 10A
    The charger will cut to 0 output rather than taper below this value.
  • Maximum allowed current: 65.535 A
    This is a meaningless binary value.
Overcharge Protection
The charger is limited by the manufacturer to a range that matches Zero's battery safe range.
The charger is connected to external AC sources and is therefore a vulnerable component while plugged in.
Per Re: Change to Charging - Leaving Bike Plugged In
  • The charger is an isolated power supply with suppressors on the input.
  • So, if a surge were big enough, the suppressors could fail short.
  • Then the circuit breaker should fail after that.
  • The BMS and the rest of the bike is completely isolated from the charger, so there's no current path to them.
This is why some people on this forum report their charger is dead, but the bike is fine, and there wasn't any fire. Most of the time Zero, replaces the onboard charger for them.
Worst-case scenario
  • BMS unresponsive
  • MBB unresponsive
  • Contactor welded
  • Charger outputs more than 117.6V
In the event of all these holding (extremely unlikely), there is some risk of a fire.
This is probably why Zero asks you to check on the bike every 72 hours to make sure the bike is still responding and the BMS is still alive.
Connections
AC input is an IEC-60320 C13 inlet.
DC output is an Anderson SBS50-BRN, but it seems to be a narrower pin pitch with no center data pin set.
CANbus signal interface is a JAE MX23A18NF1 connector (applies to the Calex, not the Mean Wells!)
CAN signal pins per GWP data sheet
Pin Function
4 CAN ground
5 CAN +5V power
6 CAN Dominant Low
7 CAN Dominant High
10 ob_charger_attached_n [charger_attached]
11 ob_charger_attached_n [charger_attached]
12 charger_en_0 [charger_en_n]
13 ob_charger_ref_0 [charger_gnd_ref]
Replacement
Since some generations of onboard chargers seem to develop faults relatively often, being able to replace a charger on one's own might save someone a lot of grief who doesn't live near a dealer.
Steps (adapted from these instructions):
  1. Unplug the motorcycle, and key it off. Wait for at least 10 minutes to ensure any residual charge has dissipated.
  2. Remove the lower plastics.
  3. Unbolt the skid pan (2 rows of 4 3mm allen head bolts on each side of the pan, and 2 smaller bolts) and remove it.
  4. Unplug the wiring at the rear of the charger area. There are three plugs, one on the AC end of things that's bolted to the bike, (your charge plug) the comm connector (enable signal, can comms etc...) and one plug on the DC side that goes up to the charge wiring harness.
    1. The comms plug just has a tab; push in the tab and pull that one out. (Both of the other plugs are really difficult.)
    2. Start with the DC plug.
      The plug is an Anderson SBS50-BRN, but it seems to be a narrower pin pitch with no center data pin set.
      The DC plug is located in front of the motor against the back side of the battery on the bike's right.
    3. The cables are tucked up between the battery and a frame member, so cut the zip ties (Including the zip tie holding the plugs together) and pull the push on zip tie mount things on the lower half of the cable going to the charger.
    4. Pull down on the charger side of the connector from the bottom while pulling up on the top connector.
      Sometimes this requires a flesh donation to the motor, so covering the motor with a rag would be smart.
    5. Pull the terminals out of the plug housing (see Anderson disassembly), and pull it down thru the hole between the motor and frame.
    6. Next, the AC plug.
      It loops up under the seat and is zip tied on in a handful of places.
      There are two small bolts on the backside that are difficult to reach, so use a decent set of hex drivers with handles.
    7. There is a fuse holder plug that connects the ground to (somewhere...).
      Squeeze some tabs to get the green locking piece out.
      Then squeeze more tabs to get the plug apart.
  5. Now with the cables out, the charger just has six bolts on the tabs holding it up. Take those out and the charger will be detached.
Assembly is the reverse of disassembly.
Suggestion
You can extended the DC wires on the replacement Calex charger, and put the plug set sideways, and up higher to make it easier to get at.
CANbus wiring
Adapted from an examination of the wiring on a 2014 SR: Onboard charger wiring for 2014 and 2015+ for the Calex.
When the onboard charger is plugged in and powered on the onboard charger pushes:
  • 5V and 48mA through the Charger attached Pin #11.
  • 5V and 26mA through the Charger enabled Pin #12.
The 5V ground reference is Pin #13 which is battery negative.
With this knowledge, another onboard charger solution can be wired to function as follows:
  1. Run a separate circuit that when triggered pushes 5V ~50mA through pin#11 (attached charger) with the other end of the 5V circuit connected to the battery negative pin #13.
  2. When this is triggered, the bike shows the battery state of charge % and charge time remaining, closes the contactor and allows charging - through the accessory charging port, the onboard charger port or via the Sevcon battery terminals for high power charging.
  3. Upon completion of charging, the 5V can be switched off and the charge level and time remaining switch off and the contactor opens just as with the onboard charger.
  4. The bike can be keyed on and ridden away as normal.
Using this method there is no need to leave the bike on when charging via the accessory charging port or the controller battery-side cables, or if you are using the accessory charging port without triggering the auxiliary pin on the accessory charging port's Anderson SBS75XBRN.
NOTE
For 2015 onwards, the charger install uses additional wiring which may have a different approach using CAN signals, so it may require a different approach.

Main Bike Board

The Main Bike Board (MBB) controls the overall system, and is the entry point for performing diagnostics. When referring to "the firmware", or "the logs", the MBB is mainly what is meant.

Location
Below the front area of the seat under cable runs on the left side.
The MBB is located above the DC-DC converter.
Connectors
MBB 34-pin connector: JAE Electronics MX23A34SF1
This connector mounts to the top of the MBB, making it relatively accessible and an obvious sign of the MBB.
Diagnostics
When using the OBD2 port, the console accessed is from the MBB.
Playing with the 2012 MBB shows Doctorbass' transcript using 2012 firmware. 2013 models' interface differs quite a bit from this but the general logic and experience are the same.

Battery Management System

This board manages the battery, of course. This is the one power drain on the vehicle when it is completely turned off with no charging, but it draws a very minor amount of power like a "sleep" mode.

The board is entirely solid state and not designed for fixing, only replacement. Any damage to this board will disable the motorcycle.

The same board model seems to be capable and used for both single-brick (FX/FXS) bikes and power pack (S/DS/SR/DSR) bikes, given software configuration changes. The board appears to be OEM-designed and has revision numbers that indicate progression over time from the 2013 model line.

WARNING
The board has full battery voltage inputs to it at all times.
Take extreme care to avoid connections that could short, arc, or ground.
Before accessing the BMS, first turn the bike off and disconnect charging so that the contactor is open and you do not interact with the BMS while it performs a cel balancing operation.
Location (S Platform)
Behind the lower front face of the battery behind the front forks/wheel.
Remove the lower front body plastics and the front battery face to access the unit.
Location (X Platform and Power Tank)
Each separate brick has its own BMS inside the armored casing.
The long brick has one BMS module inside the armored casing.
Protections
The board is mounted with rubber vibration dampening.
The board is layered with a very thick coating ("dam and fill potting") to protect the components from moisture and shock damage.
The rubber pads covering reset buttons and LED indicator lights (for 2015+ models) have dielectric grease coating (CP70 datasheet) those components.
  • The covers are not there to make it waterproof, only to keep the dirt out of the grease.
  • MY13 bikes had no grease. MY14 bikes had a different grease that did not age well, and CP70 is worth applying to both MY13 and MY14.
  • Maintain that coating and do not pressure wash the front of the battery casing to avoid damaging this board.
Inspecting
If the BMS stops working (no indication from the lights, no response to reset), the appropriate, non-warrantee-risking thing to do is take it to a dealer and they'll likely replace it under warrantee.
But if a dealer visit is difficult or there's an emergency, a visual inspection might inform what's going on (naturally, a bike that doesn't work feels like an emergency; use your judgement).
Basically, uncover the BMS and look for burned out components.
There is a large pin connector which may be loose, which would explain a loss of power to the BMS. Apparently this is very difficult to work with but can be re-attached carefully.
Don't loosen the BMS mounting without a very good reason - it's always connected to battery cell voltage by some pins on the side that run into the batter pack so a spark there might be damaging.
If you are going to lift off the BMS, take extreme care with the fasteners and dampeners to not drop them into the battery casing.
You'll also need to restore each and every fastener and dampener because the BMS mount prevents vibration damage.
Replacement Parts
Port cover pad/window
Rubber Mounting Spacers
  • Spec: ID 11/32" (8mm, oversized for M6), OD 1/2", Thickness/Length: 5mm (12.5/64"), black rubber
Potting
  • Spec: ???

BMS Reset

For a number of errors, the official manual recommends resetting the BMS.
2015+ Steps:
  1. Key the bike off and unplug it from charging. Wait for the contactor to click open.
  2. Uncover the two rubber pads on the front of the batter case facing the front wheel.
    BMSwindows.jpg
    The upper pad covers a string of small LEDs, one red on the left followed by four green. They'll indicate charge level when the bike is keyed off.
    The lower pad covers a white plastic port coated in dielectric grease. Above that port are two small micro-switch buttons which are the reset buttons.
  3. Press to reset
    The button on the left as you face performs a hardware reset. The right button performs a software reset.
  4. Take a pen (say) and depress the (right) software reset button for a few seconds and then release.
    Expect the upper pad's LEDs to go dark while the button is depressed and then turn on again when release.
    The lights should stabilize after an initial startup sequence for a few seconds.
  5. Check whether the error code is clear by keying on the vehicle or whatever is appropriate.
  6. If the error is still present, try the (left) hardware reset button in the same way. Then try both at the same time.
  7. Replace both pads.
2013-2014 Steps:
  1. Key the bike off and unplug it from charging. Wait for the contactor to click open.
  2. Uncover the rubber pad on the front of the batter case facing the front wheel, below the window for the BMS indicating lights.
    The window covers a string of small LEDs, one red on the left followed by four green. They'll indicate charge level when the bike is keyed off.
    The rubber pad covers a white plastic port coated in dielectric grease.
  3. Press to reset
    There is only one reset button above the plastic port which performs a hardware reset.
  4. Take a pen (say) and depress the reset button for a few seconds and then release.
    Expect the upper pad's LEDs to go dark while the button is depressed and then turn on again when release.
    The lights should stabilize after an initial startup sequence for a few seconds.
  5. Check whether the error code is clear by keying on the vehicle or whatever is appropriate.

Cell Balancing

The BMS connects to the battery cells via the interconnect wiring and can sense cell voltage and feed small amounts of current to cells that are abnormally low in order to maintain battery longevity and minimize the possibility of cell damage.
There are 28 contacts on the left side of the back of the board (as viewed from the front of the bike looking at the battery) which connect to each cell in the "brick" series. It detects voltage levels on all cells, through interconnects between bricks that harness each cell in the same position in the brick's series, and through this same path able to balance cells by targeting current to the cells with the lowest voltages.
Cell balancing because of the limitations of this circuit can take a long time and is part of why Zero recommends keeping the motorcycle plugged in when unattended by default.

Precharge

The BMS has a precharge circuit for ensuring that the contactors can close without causing damaging current spikes to the controller or other components.
Precharge is necessary because of capacitors in the controller; connecting sets of capacitors electrically requires care to match voltages because of the rate at which capacitors will charge and discharge to each other to balance potentials.
Precharge supplies a low amount of power (fused at 10A) to the controller-side main bus when the motorcycle is keyed on.
Voltage should climb above 85V within 4-5 seconds of powering on. At this point, the BMS measures the voltage on both sides and decides to close the contactors.
If this process fails, precharge will stop and then the voltage level will decay. You will likely see error code 25 for a precharge error on the dash (when error codes are selected for display).
The precharge circuit is not isolated from the controller or accessory charging port, and can be damaged if a large transient current is induced from an outside source to a de-energized motorcycle.
Precharge Failure
A recent (mid-2016) firmware update improves the robustness of the precharge logic especially when used with accessory charging systems that are permanently connected to the vehicle.
If while starting the bike, the sequence completes before the contactor closes, the green run light for the motorcycle will flash until the contactor does close.
To address a failed precharge on startup:
  1. Key the bike off if after several seconds, the contactor has not shut with an audible click and the green run light is still flashing.
  2. Wait 2 seconds (ensuring the dash indicator goes fully dark) and then key the bike on again.
    This should allow precharge to get a boost from residual charge from the last precharge startup cycle.
  3. Repeat a few times if necessary. If the contactor never shuts, check the logs and any error codes.

Charging Control Unit

The Charging Control Unit (CCU) collects battery temperature sensor data, battery voltage, and charger DC voltage to decide on whether to open or close the contactor.

Connectors
CCU 18-pin connector: JAE Electronics MX23A18SF1
TODO
more from Burton's post here: http://electricmotorcycleforum.com/boards/index.php?topic=3987.msg25494#msg25494

The contactor protects the battery against faults. It is analogous to a circuit breaker. The CCU directs it.

2012-2013 models exhibited behavior where the BMS in certain situations yielded a "contactor welded shut" condition that require dealer servicing. Later model years fail more safely (open).

2014+ models reportedly do not have a CCU so it's not entirely clear how contactor control is mediated or directed; presumably the BMS directly controls it with MBB signals, but the BMS design did not noticeably change.

Location
On the top surface of the battery box against the rear edge.
WARNING
This is always energized. Any exposure of this at any time will risk direct contact with battery terminals that could result in injury or equipment damage. DO NOT UNCOVER this without professional-level care!

If you are in a remote location, and have trouble with a contactor unit not closing without any indication of a particular condition that interlocks it in the BMS, a little mild mechanical agitation (while the vehicle is keyed off) against the top surface with a rubber mallet might loosen it.

DC/DC 12V converter

This is designed to produce low voltage DC power from the voltages meant for the controller in the same vehicle. It usually produces 14V DC and has an overall capacity of 300W. It's unclear which model-years have what converters, because the converter is located where a label read is inconvenient. Both of these brands have been spotted:

Location
Below the front of the seat under cable runs and the MBB.
Quick and dirty illustrative video of how to find and access the converter
Connectors
Input and Output connections are mostly on the left side.
Operation
The input side is always-on DC from the battery, upstream of the contactor. This is the best place to tap for an always-on power supply.
The converter controls its own operation, possibly using proprietary code triggered by a CAN bus message.

Firmware Versions

Using the Zero App to download the logs, and Phreak's Log Parser Utility (forum, Github, online), different users have reported the latest firmware versions to be:

Firmware
MBB BMS
Board Year Revision Version Revision Version
2013 1 67
2014 1 44 1 43
2015 3 25
2016 3 49
2017 12 21

Feel free to update this section as you discover new available updates.

Upgrading Firmware
As of 2017, Zero models are capable of performing remote firmware updates by the customer using the mobile app.
Apparently this doesn't transfer to older models because the older boards did not have enough storage space to perform an atomic/reversible update.
This means holding both firmware versions and being able to toggle which version to use.
So, if anything goes wrong with a firmware update, the system can roll back to the previous version without requiring a dealer visit.

Battery

Basic Concepts
Metaphorically speaking, think of a river and a reservoir.
Volts
water pressure.
Amps
volume of water flowing.
Charge (Kwh)
how much water is behind the dam.
Power (kW)
the rate at which water is flowing.

The following guidance includes advice adapted from MostlyBonkers' research summary and Battery Notes from a Farasis Engineer.

Charge Tips

  1. If you run your bike to empty, do your best to give it at least a partial charge (ideally to 40-50%) as soon as you can.
  2. Charge and discharge your bike freely and at your convenience.
  3. Don't worry about keeping the bike topped up, like standard car batteries.
  4. Don't feel you have to run the bike to empty before re-charging, it's fine to charge if you've only used 10%, for example.
  5. If you can afford extra chargers to reduce charging time, Zero's fast chargers won't hurt the batteries.
  6. Use the bike as much as you can. If you aren't using it for a regular commute or aren't lucky enough to have the freedom to ride regularly then it will work out a lot cheaper to own a conventional motorbike.
  7. Zero's engineers have done the work to ensure a long service life from their battery packs and have backed it up with a five year warranty with the 2014 model range onwards. That should be enough to drop any anxiety you may have and just concentrate on enjoying the bike.

Battery Capacity

Normally, the true energy a battery can have is calculated by taking nominal voltage times the Ah capacity of the battery = Wh (divide by 1000 for kWh units).

However for some reasons, based on industry convention, Zero calculates battery energy (the kWh) by taking the maximum voltage the battery has at 100% capacity times the capacity in Ah, instead of nominal voltage.

Maximum voltage is only present at the beginning of discharge when it is full, and then it drops (nonlinearly).

The nominal voltage is like the average voltage the battery over the entire discharge range. The average is the voltage measured at the battery terminal when it has 50% charge state and is disconnected from any load.

For example, the 2013 S has 100Ah and a nominal 102V: the total energy the battery has is 100Ah x 102V = 10200Wh (10.2kWh). But if you use maximum battery voltage you get 100Ah x 116V = 11.6kWh.

This also applies when adding a power tank, confusing customers about the official rating versus what the mobile application reports.

Regardless of this complexity of measurement, Zero's range figures appear reliable in the general context of the test conditions.

Cells

The current manufacturer is Farasis who are supplying pouch cells for the 2013+ model range.

The chemistry used is Lithium Nickel Manganese Cobalt: LiNiMnCoO2 ("NMC" or other rearrangements of those letters).

NMC is a relatively new battery chemistry which differs from the Li-cobalt chemistry we are familiar with from mobile phone batteries and laptops. While Li-cobalt has a higher energy density than NMC (storage capacity per kilogram), it doesn't cycle as well and ages quicker. That's fine for a mobile phone that is likely to be obsolete after 2-3 years, but not for an electric bike.

The automotive-grade NMC cells that Farasis supply should easily satisfy the requirements of the five year warranty that Zero are providing with their current Z-Force battery packs. It seems they should last 8-10 years if they aren't abused. Even if you start to notice some significant deterioration after five years, the rate at which battery technology is progressing means that you should be able to buy a new battery pack with much better capacity (range) than the original for substantially less money.

It's worth getting a battery pack that provides perhaps 50% more range than you require for your commute or average needs, so that you can suffer some loss of capacity and still have a safety reserve. That way you never need to worry about it and you'll easily get your 8-10 years of useful service by which point you've certainly had your money's worth from the bike and can upgrade.

Farasis claims:

25Ah cells (2013-2014 MY, 2015FX)
The 25Ah cells are a solid cell, and are Farasis's oldest chemistry design. They are a manganese-rich cathode (NMC) 25Ah cell with excellent cycle life, and acceptable C-rate.
27Ah cells (2015 S/DS/SR)
The 27Ah cell introduced for the model year 15 bikes is an adaptation of the 25ah cell chemistry with thinner foils and more of them, this means that there is more active materiel (more capacity) but less conductive path to get that capacity in and out. So for the slow discharge S/DS bikes, you get more capacity, but they are lower C rate, and cannot handle being used in the FX platform.
29Ah cells (2016-2017 MY)
The 29Ah cell is Farasis's newest generation of NMC cell, and they are "awesome" (words of Farasis engineer).
They have both higher discharge rate (peak and continuous) than the 25Ah cell, and more capacity (especially at higher C rates/cooler temperatures) than the 27.
Cell dimensions
160 x 230 x 6 mm (for 29Ah version)
Voltage
3.65V nominal

Further reading: 2014 ZERO BATTERY CHEMISTRY (Z-FORCE® POWER TANK SECRET SAUCE)

Cell Arrangement

Notation

Configurations are listed like "28s4p" referring to a stack of 28 cells in series with 4 stacks in parallel (for the Z-Force Power Pack for S/DS/SR/DSR models). "1p" refers to the single stack used for the FX or the Power Tank module.

Bricks

The stacks of cells form modules, and are referred to as "bricks" because they're bathed in an epoxy after assembly, so a battery is often described as a "3 brick" or "4 brick" configuration.

For 2014+ S/DS/SR/DSR model years, installing the Power Tank changes a "4p" to a "5p" (and presumably "3p" to "4p" but this seems unlikely).

The 3p arrangement for 2013-2016 S/DS models uses the same "monolith" shape but leaves the forward upper quadrant empty (presumably filled with lightweight but load-absorbing material).

Long Bricks

The 2p arrangement for 2017 S/DS models has a "half monolith" or "long brick" shape, and leaves the rear half of the monolith area in the frame empty for a storage bin accessed from the side of the frame.

The long brick arrangement seems to represent a more efficient layout and saves some amount of weight from the interconnects.

Monolith Packs
For 3- and 4-brick monolith packs (28s3p and 28s4p), an interconnect wiring system electrically connects each cell across bricks that is in the same position in the series.
This minimizes the complexity of cell balancing by ensuring that only 28 conductive connections are needed from the BMS to keep cells balanced.
It also ensures that a set of 3 or 4 cells are electrically able to balance a certain amount of load, reducing stress from imbalanced load variations while running.
For 2017 packs, made with "long bricks", the interconnects are extremely simple, only connecting two stacks which are aligned directly against each other. 2017 monoliths consist of two "long bricks" with simpler interconnects.
Battery Configurations
Cell Configuration
Form Model Voltage Years Platform Series Parallel Voltage
cylindrical Molicel 26700 2.9Ah 3.8V 2009 S 14s24p 14 24
48V (min)
53V (nominal) ≈ 3.8V × 14
58V (listed/max)
2010-2011 X 14s12p
S 14s24p
pouch EIG C020 20Ah ([2]) 3.65V 2012 S/DS/X/MX/XU 18s2p 18 1 to 3 for ZF3, ZF6, and ZF9
66V ≈ 3.65V × 18
Farasis 25Ah 2013-2014 X 28s1p 28 1 or 2 removable
116V (max)
102V (nominal) ≈ 3.65V × 28
84V (min)
S 28s3p or 28s4p 3 or 4
Farasis 25Ah 2015 X 28s1p 1 or 2 removable
Farasis 27Ah S 28s3p or 28s4p 3 or 4
Farasis 29Ah 2016 X 28s1p 1 or 2 removable
S 28s3p or 28s4p 3 or 4
2017 X 28s2p 2 (fixed), or 1 or 2 removable
S 28s2p or 28s4p 2 (with storage) or 4
Battery weight estimate
For 2015, each brick weights 32 lbs.
4 bricks would be 128 lbs, but the base plate, BMS, dog house with contactor, current sensor, fuse, and connectors add enough to make the total about 140 lbs.

State of Charge

Theory

State of Charge is a measure of the battery state meant to help estimate remaining energy. However, it is an abstract / simulated measure, not one that can be directly proven with enough physical inputs: the actual proof of state of charge is to fully discharge the battery, running an integral of current as discharged. But a "full" discharge is determined by software, too, measuring minimum cell voltage, which sometimes (and possibly for certain cell generations) can have a single cell fall in voltage early causing SoC to drop early. And this voltage can be a dynamic result of discharge, so that restarting the bike after a few minutes' rest period can show a higher SoC than before.

Batteries are chemical systems that can be very complicated to summarize; one of the main factors that determines how much energy a battery will be able to release is its current temperature, which is determined by both outside temperature and any heat produced internally from resistance during charging and discharging.

Zero's algorithm looks at the current pack voltage (seemingly the most accurate sensor) to estimate charge state but also measures current in a less precise way to measure charge/discharge rates. And it also measures battery temperature which may correct for some factors.

Example

For the Farasis 25Ah cells (using the datasheet available), noting a 28 cell series, the 116V reported by the mobile application at 100% SoC corresponds to 4.14V (=116V/28). 0% state of charge at least naively then would correspond to 92.4V ( = 3.3V × 28).

The nominal cell voltage listed (3.65V) then corresponds to a nominal pack voltage of 102.2V, which does reflect the relatively stable battery voltage reading near the middle of the state of charge cycle in steady state.

In any case, the state of charge calculation is driven by attempting to bracket vehicle usage to stay in this range - the desired voltage range (to maintain battery chemistry over the stated lifetime) drives stated limits, coupled with an estimation of the amp-hours remaining from any given point in the collective state of the battery pack.

Alternate Framing (per Terry)
Zero will let you discharge to about 88 volts and up to 116.4 volts.
By the Farasis data sheet, this is using the full capacity of the cells with the exception of about 4 volts from the whole pack.
84 volts would be 3.0V per cell but 88 volts is pretty close.
88 volts is about 3.14V per cell and there is less than 1% energy left at 3.14V.
SoC Indications per protomech
  • The phone app appears to simply show kWh using Zero's max capacity rating, i.e. present voltage times present amp hours.
  • The voltage and amp-hours are likely to be correct, but the kWh readout is a rough guide at best.

Battery Storage and Capacity with Age

Chemically, the cells mainly age in two ways:

  1. The electrolyte reacting with the active components of the cathode and anode in the cells, and releasing gas (calendar life).
  2. The interaction between the lithium ions and the anode/cathode blend that causes a small amount of damage each time they are cycled. (Cycle life)

You just have to come to terms with the fact that from the moment the battery pack is manufactured it will very slowly lose overall capacity regardless of whether you use it or not. Li-ion batteries are good at holding their charge so you don't need to worry about letting them stand for a long time, providing they've got a reasonably good state of charge (SoC). At 40-50% SoC the overall capacity loss due to aging is minimized. At full charge the aging effects are increased but not by such a great amount that it should cause any great concern. For some owners it might be wiser to follow Zero's recommendations and just leave the bike plugged in for however long you plan to store the bike. This at least makes sure the individual cells stay balanced with each other and there's little risk of them dropping to a very low SoC at which point the aging effects begin to increase. If you let the SoC drop below their minimum threshold you run the risk of the battery pack becoming unusable. I think that's why Zero recommend leaving the bike plugged in over winter. If there's some sort of power cut mid-winter and the bike isn't checked for a few months, then at least there's a good chance the battery won't have discharged too much.

Farasis recommendations:

The manufacturer might state that you will get 500 cycles from a battery and they will be referring to full cycles. However, if you only ever use 10% of the capacity from a full charge and then top it up, you will get more cycles from it before the battery health drops to 80%. In this example you are likely to get 1500 cycles from a battery that you only ever discharge to half it's capacity. That's assuming that all other variables remain the same. In day-to-day use, variations in state of charge and temperature are more likely to affect battery life than how you cycle the battery. Taking Zero's claim's of an estimated battery pack life of 496,000 km using city ranges it would take at least 2,250 full cycles to achieve this (2014 Zero S 11.4 kWh). Taking into account the loss of capacity in this period and the figure is bound to be more like 2,500 cycles. Most trips and daily commutes will probably drop the battery to 40-50% SoC thus increasing the number of cycles we would get from the battery. Let's say we average 60 miles between charges of a 100 mile combined range over the life of the bike. Then let's allow ourselves 3,000 cycles before the battery drops to 80% health. That's still 180,000 miles. Even if we then halve that to allow for temperature and aging (very unlikely even in harsh conditions) we get a very, very conservative estimate of 90,000 miles. That should give even a heavy commuter a good five or six years of use before noticing significant reduction in range. Even then, a daily average of 60 miles would still give you a 20 mile reserve.

If you do decide to leave it at 40-50% SoC you also need to be organized enough to check the bike every couple of weeks or so. It wouldn't hurt to charge it up after a few months, leave it plugged in for a few days to make sure the cells get properly balanced, then take it for a ride to bring the SoC down to the 40-50% level again before leaving it for the next few weeks or months.

I have no doubt that the good people at Zero have done their sums, know the specifications of the batteries in detail and are confident that their battery packs will have at least 80% health after five years even if the bike is never ridden and left plugged in all the time. Zero also state in their specifications that their battery packs are good for hundreds of thousands of miles before they reach 80% of their original stated capacity. That in itself should be enough to put your mind at rest, but if it isn't then perhaps these golden rules should help:

  1. Don't leave the bike standing empty for more than a few days.
  2. If you have to store the bike for a long time, then either leave it plugged in and don't worry about it, or leave it at 40-50% SoC but keep an eye on it.
  3. Just use your bike as much as you can and don't worry about the battery. The engineers have thought all this through and are backing it up with a five year warranty. The whole scene will be different in five years time, so it isn't worth thinking about.

Battery Temperature Effects

Performance
Battery internal resistance is higher at lower temperatures, which means that while riding, losses to battery internal resistance mean a loss of range at lower temperatures.
Farasis quotes internal cell resistance as <2mΩ but it's not exactly clear how this translates into calculating those losses without some description of how that trends over temperature and charge rate.
The warmer the battery is, the lower these losses will be.
Below freezing temperatures, the battery chemistry will not allow effective charging at all, and Zero provides protections to prevent this until the battery's temperature has been raised sufficiently.
It follows that to get maximum performance, charging and discharging repeatedly at a high rate will raise cell temperature enough to reduce internal resistance so more will be delivered to the motor.
Degradation at high temperatures

Temperature is a bigger factor than state of charge when it comes to aging. Apparently, for every increase of 10F degrees in battery temperature across its lifetime, battery deterioration over that lifetime can double.

Heat Production
It is worth noting though that Li-ion batteries shouldn't generate a lot of heat when charging at normal rates.
On a Zero, charging at or below 4kW will not produce much heat.
Therefore, even if you live in a hot climate and have just been on a ride, the cells should cool down overall even while they are charging (although direct sunlight on the battery will add more heat).
You might want to be a little more careful if fast charging in a hot climate but don't forget that the BMS will either reduce the charge rate or stop charging altogether if the cell temperature exceeds the limits that the engineers have set. They have set these limits on the conservative side to avoid any claims on that five year warranty.
Storage
If you are going to store the bike, it makes sense to store it somewhere cool.
Fridge temperature is probably best but never store below freezing.
If you don't have the option of storing it somewhere cool, then don't worry about it.

Battery Memory Effects

There are no memory effects with Li-ion chemistry. Some 'Smart' battery management systems might recommend performing a deep discharge followed by a full charge from time to time. This helps re-calibrate the system and give better estimations of capacity remaining. However, there is no need to do this from purely a cell maintenance point of view. All Li-ion batteries have protection circuits to keep the cells within their safe operating voltage range. You can therefore simply charge and discharge at will and not worry about charging a battery that is half full.

Rate of Charging and Discharging

The Farasis cells have a nominal capacity of 25 Ah (2013-2014). Each cell has a maximum continuous discharge rate of 100 A (4C rate). You would have to discharge the battery in 15 minutes to achieve that, which is impossible to achieve normally.

Conveniently, the Zero S 11.4 should achieve a range of approximately 70 miles at a constant speed of 70 mph. That would result in a full discharge in an hour. Even maintaining 80 mph, the maximum sustained speed of the bike, it's difficult to empty the battery pack in less than half an hour. So the cells are operating well within their specifications.

The maximum charge rate for Zero battery packs is 25A for each cell or brick (2013-2014), which would mean a full charge in an hour, referred to as a 1C rate. Even with 2 x 2.5 kW Elcon chargers, you're only going to get a full charge in 2 hours, probably more like 2.5 hrs as the charge rate will drop as the battery reaches capacity. Yet again, the cells are under relatively little stress even with a fast charge.

Protections

Contactor

The contactor mutually protects the battery and the bike's systems from damaging each other, particularly for rush currents or overcurrent conditions.

Model
The 2013+ Zero contactor is a GIGAVAC HX or GX-series contactor.
Location
The 2013+ contactor is housed within the "dog house", an enclosed area extending from the main power pack enclosure top face at the rear.
Behavior
See Charging Control Unit and Contactor Limits.
Theory (ref)
A contactor is a large relay: it allows a fairly small voltage/current signal to switch a much larger voltage/current.
It has two sides:
  1. The drive/coil side (control).
  2. The load (contact) side.
On the drive/coil side, there's a "kickback" diode which handles the inductive spike caused when the drive to the coil ceases.
Without that diode, the energy represented in the magnetic field inside of the coil would have no place to go, so it would cause a voltage spike which can be damaging to components.
The kickback diode gives that energy somewhere to go, allowing it to ramp down fairly slowly without a big voltage spike.
Depending on how the coil side of the contactor is wound, it has a certain current requirement to pull the contactor shut, say 12V @ 100mA, which will be provided by the driving circuitry.
There's not necessarily any relationship between the coil rating and contact rating, except that bigger (higher-current rated) contacts might be heavier and require higher coil current to get the armature to move.
The kickback diode only needs to carry this amount of current, regardless of the contact side current.
If a 3A kickback diode is specified for that contactor, it will be adequate for any contact side current.
The make/break current is the rating for the contact side of the contactor.
You won't actually want to make or break the contactor under the limiting conditions (you'll always want to both make and break the contactor at exactly 0 amps), but in an emergency, it's rated to do so without the contacts welding together -- and an emergency is what the contactor is there for.
In automotive use, you often see the coil set up for 12V, drawing maybe 100mA (the current can vary widely though).
That small current pulls the contacts together, which switches on the high-current side.

Contactor Limits

Zero's effective contactor limit for the charging rate is 95% of 1C rate.

The BMS will open the contactor for the following conditions:

Inactivity
If the motorcycle is keyed off and not otherwise set in charging mode, the contactors will open after a few seconds.
If the motorcycle is keyed on and not otherwise set in charging mode, and then 30 minutes pass without control input.
Twisting the throttle is sufficient to reset this timer; otherwise restart charging once it happens.
Voltage
Voltage is too low or too high outside its safe operating range.
If voltage is too high (117V):
  1. Confirm with the Zero mobile application
  2. Attempt to bring it back to normal range by discharging the battery:
    • operating the motor (fastest but requires a closed contactor, and the Sevcon won't operate above 118V) or:
    • turning on all available electrical loads.
If voltage is too low, charge by any means necessary:
Prefer the onboard charger or an equivalent rate source through the charging port.
In an emergency, the regen feature can be used to charge the battery through the motor.
Drive the motor by spinning the rear axle with a suitable power source, with the bike in Custom Mode with regen set to 100%.
Power
Incoming power exceeds 1C rate continuously for a minute. A 1C rate charges the battery fully in 1 hour.
For a battery with 13 kWh max capacity, this value will be 11.4 kWh nominal / 102V = 110A (say).
If the charge rate is too high for the battery, downgrade the charge rate manually and restart.
Field testing indicates that the short time setting for the contactor opening is 30 seconds, and that a 20 second period under that limit will reset it.
This may vary due to environmental conditions like ambient temperature.
Temperature
If the battery temperature (not ambient) is outside safe operating bounds:
Lower limits
0F charging prevented
-22F operation prevented
Upper limits
110F charging tapered
122F charging prevented
140F operation prevented
The Zero battery will emit heat while its charging rate exceeds 4 kW, and it will cool if under that threshold.
If temperature is out of safe range, do whatever is appropriate to bring the temperature back in range.
Calculating Contactor Limit Per Bike

Per Zero's specs pages:

Maximum kWh = (# of cells) × (cell Amp-hour capacity rating) × (cell max voltage rating)
Example
A 2015 SR w/ Power Tank has 15.3kWh max, 13.5 kWh nominal, with a 102V nominal voltage, so is nominally rated at 133 Ah.
1C rate means that it can charge at up to 133A.
At 10% actual SOC (3.4 volts per cell), 1C = 3.4 volts per cell × 28 cells in series × 133 A = 12.7 kW.
At 95% SOC (4.1 volts per cell), 1C = 4.1 volts per cell × 28 cells in series × 133 A = 15.3 kW.
These are DC power ratings; AC input power will read 10 to 20% higher (due to conversion losses).
Charging Limits
Capacity (kWh) Voltage Capacity Contactor Limit
Year Cell # Bricks Max Nominal Max Nominal (Ah or 1C amps) A (95% assumed)
2013 25Ah 4 11.4 10.0 116 102 98 93
2014
2015 27Ah 4 12.5 11.0 108 103
2016 29Ah 4 13.0 11.4 112 107
2017

Battery Fuse

Each "brick" has an internal 300A fuse for protection in case the contactor welds shut (very difficult if not impossible by design in post-2013 models).

Naturally, if this fuse blows, your battery warranty may be in question, and certainly if you open the pack to replace it.

Battery Stress Factors

The following factors speed up degradation:

Hot Temperatures
This causes the electrolyte to become more reactive. Farasis claims to have one of the most stable electrolyte blends in the business, and use a lot of proprietary tech to keep the cathode/anode blend as least reactive as possible, but the effect is unavoidable.
High Voltage
Again, The higher the potential between the cathode and anode, the faster the reaction between the electrolyte and the actives occurs.
Very Low Voltage
Below a certain voltage (2.0-2.2V/cell) the potential between the cathode and anode is such that the battery has used all its high potential lithium, and so it starts picking on the next easiest thing, which is the copper.

This process is super ugly, as it electroplates the copper off the negative foils (anode) and electrodeposits it onto the positive foils (cathode). PERMANENT IRREVERSIBLE DAMAGE. This is super dangerous too, as the next time it is charged, that copper gets blasted back to the negative foils and lands wherever it feels like, as the anode isn't designed to deal with copper Ions. So they form big crystal sharp structures called dendrites, which at best can pierce the separator and cause high self discharge and gassing as the electrolyte nucleates (gas builds up, the cell goes to 0V and looks like a balloon) , or at worst, the dendrite is able to get a solid connection between the cathode and anode, and this causes the cell to short internally and results in fire. Luckily for you, Zero has an amazing BMS and pack topology that sips hardly any power from the cells in a key-off state, but you still can murder the bike by approaching 0% SOC as slowly as possible until it is at its absolute lowest SOC (state of charge) and the BMS shuts the bike off. What happens is that the bike has the smallest amount of reserve battery then, and the BMS sipping away at that small amount will eventually murder the cells over a period of several years.

Battery Longevity

If Zero are putting a five year warranty on their battery packs, it's quite possible that they believe they will last ten years. Tesla are saying that their battery packs are good for 15 years apparently. It seems a lot like buying a normal bike or a car. Feel confident that it will give you at least five years or 50,000 miles of good service. If you don't mind buying a five year old vehicle and taking a bit more risk, then you should achieve double. Time will tell and sellers will be able to quote actual range figures to prospective buyers.

Battery Future

Battery technology is improving every year, but not at the same rate as computer technology. A 10% per year increase in capacity might be a reasonable expectation. We can always hope that there will be a significant breakthrough that makes is way to production and changes the state of the art much quicker. For the time being though, we have robust technology that should give you five to ten years of service and a range of about 100 miles of mixed riding as long as you don't spend much time on fast roads. It's perfect for many city commuters and people who like relaxed rides taking the country roads. You will need an ICE bike for longer journeys and touring, unless you are willing to plan in long charging stops. If you can use your bike for your commute or have regular trips that cover less than 100 miles a day, then range anxiety won't be an issue.

Battery Best Practices

Basically, the way to kill a Zero the fastest is to either ride it to absolutely dead as possible, and then store it in a shed for six years, or to store it at absolutely tip top charge in direct sunlight in a super hot desert in Arizona somewhere. Either way, you will still struggle to kill them before the warrantee is up.

So, to prolong your battery life, you can do the exact opposite. Store the bike in a cool place with a stable temperature at a medium SoC. About 60% or so is fine for S/DS (one BMS sipping on 3-5 cellboxes) or 70% for the FX modules (one BMS per cellbox).

When you get done riding your S/DS hard on a hot day, let it cool down for 4-6hrs before charging it.

This takes less time for FX modules.

Fast charging is fine, but know that around the .8C mark is the point where at normal ambient temp, you go from cooling off to heating up. If your pack is already hot from a ride through the desert at WOT, and you fast charge, you are still going to be on a hot pack when you continue your WOT journey. This is not a big deal, but it's helpful to bring the battery temperature back down to minimize the aging effects that this accumulates over time. The BMS will keep you from really breaking your pack, so don't worry about it.

Construction

The Power Pack is a heavily armored box case.

Dimensions for the full Power Pack are 10" width, roughly 17" height and 14" depth.

The "long brick" enclosure for 2017+ models is the same at roughly half the depth, and of course the storage area on S/DS models with this Power Pack has about the same dimensions minus clearances and dividing bracket allowances.

Battery Removal

X Platform
The OEM manual covers this, and it's a primary feature of the X platform that the power packs can be swapped or removed.
As of 2017, X platform models (FX/FXS/FXP) are assembled by default with a "long brick" 6.5kWh pack that cannot be easily swapped or removed; it is bolted into the frame. The option to buy a model with individual power pack modules is still available for an additional cost.
S Platform
This is very involved, only suitable for a dealer or experienced electrical engineer equipped with a hoist, because the frame must be lifted vertically off of the battery, and the battery must be electrically detached from the systems safely.
There is also almost no realistic reason to do this for a battery under warrantee.
Steps below are a rough sketch of the process.
  1. Remove the belly pan and onboard charger.
  2. Disconnect all cables leading to the battery.
  3. Place the motorcycle on a center lift that can balance the battery on its own.
  4. Harness the frame into a hoist and put some of the load onto that hoist.
    The hoist should be rated to lift the bike's weight entirely.
  5. (Possibly) remove the front wheel and/or forks.
  6. (Possibly) remove the rear wheel and/or swingarm.
  7. Use an allen key wrench to remove the 2 bolts on each side of the lower battery mount (4 total).
  8. Lift the frame?

Battery Pack Rebuild

This is the most unrecommendable thing to do for a Zero owner who is not an experienced electrical engineer. The battery warrantee will be completely forfeit, its watertightness will be compromised, and there is likely little a non-expert can do to improve the design. And you could be killed.

For older Zeros whose battery warrantee has expired, contact a dealer or Zero's corporate technical support line to see what they can support. Zero has in the past offered reasonable trade-in value for older motorcycles which are difficult to support and rare.

It is conceivable but entirely unconfirmed that pack upgrades or recycling trade-ins might be offered years after a model is released.

One rebuild report: 2010 Zero X Battery rebuild with pouch cells

References and further reading

Charging

The Charging Control Unit (CCU) and Battery Management System (BMS) manage charging and manage a contactor to prevent charging in a number of conditions. The contactor makes an audible “click” sound when closing and opening. Don't twist the throttle after turning the bike on until you hear that click; the bike prevents itself from lurching forward if the contactor closes while the throttle is open, but you shouldn't rely on that or find yourself surprised.

Similarly, do not start charging without a closed contactor. The onboard charger will enable charging mode by CAN bus communications, or keying the bike on can at least close the contactor for drive mode. Charging mode can be retained through charging port inputs at the signal pins, but they cannot initiate charging mode.

Charging Indications

External
The dash charging light will flash while charging.
The dash charging light will be solid once fully charged.
The BMS front indicator window shows 4 LEDs. The number of LEDs lit indicates the SOC level in quarters.
Voltage (verifiable with the mobile app)
Battery voltage will rise with its state of charge while charging from below 20% and then stays relatively constant (easing from 100V to 104V) from 20% to 80% where it starts rising again.
A Zero battery will have a full charge when it has 116V while at rest.
During a charging session, the voltage will dynamically increase by as much as 1V so expect 117V at the end of a full charge until charging stops.

Indications for the Zero battery state of charge while charging may have a significant inaccuracy at high charge rates, and typically report lower than actual towards the upper end of the range (80% - 100%). Turning the motorcycle off and letting the contactor open and waiting for several seconds should restore charge accuracy.

The battery will charge most efficiently between roughly 20% and 80% state of charge, with voltage high enough that current limits allow more power input. At higher voltages, chargers taper out of concern to maintain battery condition.

Charging Heat

The Zero battery will emit heat above a charging level of 0.4C (4kW for a 4-brick pack), and will naturally cool below that threshold. Expect several degrees Fahrenheit rise when performing a full charge near a 1C rate.

Discharging a battery at a very high rate can also produce heat. If the battery temperature is already high enough to cause concern about the next charging phase, ride at relatively modest speeds to allow ventilation to cool it faster than discharge heats it up. Use a battery temperature indication to help understand this.

On-board Charging Port

The onboard charger is connected to an IEC C14 inlet hard-mounted to the lower left side of the frame above the footpeg.

A rubber plug is included to protect the inlet from the elements (which then protects the onboard charger from sparking currents that can degrade it over time). Keep the rubber plug on when the inlet is not connected to a cord.

MY2016DSR onboardchargerconnector dustcap.jpg

Replacement
  1. Remove the left pillion footpeg bracket
    MY2016DSR onboardchargerconnector fasteners.jpgMY2016DSR onboardchargerconnector pillionbracketwrench.jpg
  2. Remove the fasteners holding the electrical receptacle
    MY2016DSR onboardchargerconnector pillionbracketremoved.jpgMY2016DSR onboardchargerconnector connectorremoval.jpg
  3. You now have access to remove/replace the rubber protective plug
    MY2016DSR onboardchargerconnector dustcapremoval.jpg

Accessory Charging Port

The Zero platform includes a charging circuit terminated by a hard-mounted brown Anderson SBS-75X connector to support OEM and third-party additional chargers.

To use
  • Remove the rubber boot cover and plug in the charger(s).
    MY2016DSR accessorychargingport stockfromfactory.jpgMY2016DSR accessorychargingport cutzipties.jpgMY2016DSR accessorychargingport removezipties.jpgMY2016DSR accessorychargingport connectchargeplug.jpgMY2016DSR accessorychargingport reseatrubbercover.jpg
    As delivered, the rubber boot cover will be secured with zip ties. Remove them first.
    2013 models do not include the rubber boot; it is a good idea to install one to protect the plug over time, though.
  • Use the onboard charger in conjunction with the accessory charging port to keep the motorcycle in charging mode (allows keying off while charging among other things).
  • Replace the rubber boot after unplugging the charger(s).
Mounted locations
Platform Years Location
X 2013+ Forward of the motor on the right lower side of the frame, under a plastic panel with 5 fasteners.
S 2011-2012 Right side of the battery.
2013 Above the motor on the right side (opposite the ODB-II port).
2014+ Above the motor on the left side (more accessible than 2013), covered by a rubber boot.
Location

DSR Charging Port from above the motorDSR Charging Port from under the tail

Charging Circuit Fuse

The charging circuit has a fuse encapsulated in a cable that protects the battery from charging at too high a rate.

Affected Circuits
  • 2013: the charging fuse acts on the accessory charging port, and does not disable the onboard charger.
  • 2014+: the fuse acts on the circuit containing both the accessory charging port and the onboard charger but has a much higher limit.
Location
On the right side of the bike under the seat behind the battery, near or under quite a few 12V cable runs.
Fuse Specification
Platform Years Current Limit (Continuous) Power Limit (Continuous) Product
X 2013+
S 2013 30A 3kW Eaton JJN-30
2014+ 100A rated, 85A slow limit 10kW Eaton JJN-100
NOTE
2013 Battery Pack Longevity Recalls
The battery pack replacements performed by the manufacturer due to discovered defects wind up being upgrades to 2015 and then 2016 model year power packs, and seem to include upgraded charging circuits, so those older models will have the higher-rated fuse and work like the newer bikes, charging-wise.
Replacement
WARNING: This fuse is not meant to be user-serviceable, and could be very dangerous to replace without the exact same specification.
The fuse is downstream from the contactor, so if the contactor is open (it should be if you can't charge and the bike is keyed off), it should be de-energized.
Verify this with proper testing equipment.
It's a huge inline fuse within adhesive heat shrink, so it's difficult to extract and replace.
The wires do have ring terminals once you get the fuse out, so you could wire in a fuse breaker. Or if in a pinch just bolt them together.
Fuse Part Investigations
A 2014 SR was found to have an Eaton JJN-100 fuse, a fast-acting fuse rated for 300V and 100A.
Datasheet for the Eaton JJN-100
If the 2014 match is correct, a JJN-30 would seem to be the match for a 2013 Zero (same datasheet as above).
There was supposition of a 60A limit on 2014 motorcycles, implying a TTN-60, but that has not been proven with evidence.

Electrical System

Switchgear

Ignition Switch

The ignition switch is a locked turn-key operation for enabling the bike with a reasonable amount of physical security.

The ignition wiring runs under the steering head to the MBB. This implies that the MBB is at least partially powered while the bike is keyed off.

Security
Position the steering in the locked position to prevent easy access to the wiring which facilitates theft/override via "hotwiring".
MBB pins (per 2013 trace)
4 - Orange/White 20AWG
5 - Orange/Black 20AWG

Handlebar Switch Housing

The handlebar switch housing assemblies seem generic but have Torx T22 security bolt fasteners making inspection and maintenance more difficult than average.

Kill Switch

The kill switch (or engine cutoff/cutout switch) prevents motor operation as a separate control from other interlocks.

It is wired as a digital input to the MBB.

Usage
Use it whenever the bike should not be operating, as a redundant safety mechanism to prevent injury or damage.
Use it if the vehicle is on its side after a crash or other incident to prevent spinning up the wheel.
Troubleshooting
The status command in the MBB console can report its reading.
MBB Pins (per 2013 trace)
23 - Red 20AWG
24 - White 20AWG

Kickstand Switch

The kickstand has a safety cutout switch to prevent motor operation while at rest.

Raise the kickstand for testing only with the rear wheel lifted off the ground via a stand or lift.

Electrical Note
The connector is three pronged and needs to be connected correctly or can cause a fault with the MBB.
Do not disconnect or reconnect while the vehicle is keyed on or contactor is shut to be safe.
Troubleshooting
The status command in the MBB console can report its reading.
MBB pins (per 2013 trace)
10 - Yellow/Black 20AWG
11 - Orange/Black 20AWG
27 - Red 20AWG

Tail Wiring

Tail wiring is fairly standard but runs by the motor controller on the left side and should be protected from chafing by the controller cover.

Schematic

Burton has been maintaining a Zero wiring diagram based on his now-highly-modified 2013 Zero S. It is schematically correct for that year but could use improvement explaining the physical routing and there are missing details like the precharge circuit.

The latest version of Burton's diagram for 2013 Model S:

Gridded
No Grid

Burton's thread with updates

Later model years have changed a bit; the 12V fuse block has more slots for ABS, at least, and the cabling layout is denser.

OBD Location

Zero OBD-II port location by model year:

S/DS/SR 2013-2015
Above and behind the motor next to the accessory charging port; usually on the left-hand side.
S/DS/SR/DSR 2016+
Under the seat on the left side just behind frame bulkhead that the tank plastics rest on for 2016 models.

OBD-II location for 2016

FX
Under the left side tank plastics.

OBD-II location for FX

Routing

S Platform
The 12V fuse block is bolted under the bracket; the underside terminals lead to the positive terminals from the DC converter below on the left side.
The terminals on top enter a mesh sleeve, through a ferrite ring to clean up RF interference, and lead forward into a larger sleeve that runs along the left side of the forward tank area.
The 12V accessory port cable is lower gauge than the others and has a crimped connection that splits into two circuits for 2014+ models.
The positive side crimped connection is just two inches from the fuse block under the first sleeve, wrapped in vinyl self-adhesive tape.

Ref. Quick and dirty Youtube guide to this areaa

The negative side connection for all of the forward 12V circuits is halfway along the tank area under a longer stretch of vinyl self-adhesive tape. The merged output leads back down to the DC converter between the forward seat and the motor.

(The following picture has one flaw: accessory port wiring and headlamp wiring are positionally swapped, or the entire assembly is installed upside down.)

Fuse block

The largest connector on the left side leads to the instrument cluster. There is a smaller 4-pin connector there for ABS circuits (probably).

The turn signal flasher relay is clamped to the underside of the front part of the frame in front of the tank, along with the Sumimoto accessory port, the SAE connector (2014+), and a 3-pin headlamp connector.

Tank Electrical Layout Connectors and relay under front frame

Towards the tail, one sleeved bundle handles the turn signals, brake and running lights, and license plate illuminator. Turn signal wires run through a pair of holes where the tail stalk meets the subassembly underneath the tail.

X Platform
The 12V fuse block is located behind the right hand front body panel.
The turn signal flasher relay is also under the right panel.
The SAE connector is located under the bundle of wires on the right side front body panel.

In the following photo, the cable is on top, but it can be routed around. It only has power when the motorcycle is keyed on. Zero FX wiring

Troubleshooting

Dash Display

System Warning
The red indicator light in the lower part of the display sometimes will flash a repeating sequence. The official manual lists what they mean, usually related to system startup. Often enough, keying the bike off and on is the way to re-test.
Display Flashes
If the dash display in its entirety is flashing after keying the bike on, this indicates an onboard charger self-test failure. Key the bike off and wait for a few seconds and retry, and it should clear.
Error Codes
Switch the dash display 1 to the error code display to see a cycling list of the 2-digit error codes currently in effect. Check the official manual for what they mean; some are normal safety interlocks and others are about various systems.
TODO document code 57.
No Backlight
Check your running lights and license plate lights, if those are also out then check the fusebox (see: seat removal).
If the fuse pops right away, there is a short circuit in the wiring harness (as happened to a MY2016 DSR pinched wiring harness (or mouse nest!) to the license plate lights).
Disconnect the tail light module and the display module connectors; if the fuse still pops, try removing the tail and tracing the short circuit.

Using Mobile App

First, check Zero's official mobile app user guide

The Zero companion mobile app can send logs to Zero customer service, or to an email address.

The logs are binary-encoded in a proprietary way.

Decoding
You can send the logs to yourself, and use a log file parser utility to do some digging which might save time if the utility can successfully decode the relevant parts.
Forum thread introducing the tool.
GitHub repository for the log parser.
Incomplete/reverse-engineered log structure documentation.
Online version of the log parser app, just upload your .bin file and view the results.
HTML/Javascript downloadable log parser, works on your Android/iOS phone to decode log files on the same device.
Upgrading Firmware
As of 2017, Zero models are capable of performing remote firmware updates by the customer using the mobile app.
Apparently this doesn't transfer to older models because the older boards did not have enough storage space to perform an atomic/reversible update.
This means holding both firmware versions and being able to toggle which version to use.
So, if anything goes wrong with a firmware update, the system can roll back to the previous version without requiring a dealer visit.

Diagnostics

MBB Console
CANbus
Zero CANBUS decoding to get and map motorcycle range
Decoding range from the CANBUS using a Raspberry Pi (LONG!)

Repair

Front brake lever

Made using MY2016 DSR, should apply to 2014+ DS/DSR and probably S/SR
FBLMY2016REPAIR02.jpg
Parts
JJUAN FRONT BRAKE LEVER SDS 25-0803201 $76 USD
FBLMY2016REPAIR01.jpg
Tools
5mm hex bit, 10mm socket.
FBLMY2016REPAIR03.jpg
Removal
FBLMY2016REPAIR04.jpg
  1. Remove bottom 10mm lock nut.
    FBLMY2016REPAIR05.jpg
  2. Loosen top 5mm hex bolt.
    FBLMY2016REPAIR06.jpg
  3. Remove top 5mm hex bolt.
    FBLMY2016REPAIR07.jpg
  4. Slide out brake lever assembly.
    FBLMY2016REPAIR08.jpg
  5. Inspect brake lever mount for damage
Replacement
  1. Remove bottom 10mm lock nut from 5mm hex bolt and set both pieces aside.
    FBLMY2016REPAIR09.jpg FBLMY2016REPAIR10.jpg
  2. Slide in brake lever assembly, taking care to align the rubber boot / plunger (what's the technical term?) and the bolt hole.
    FBLMY2016REPAIR11.jpg FBLMY2016REPAIR12.jpg
  3. Insert 5mm hex bolt from top to bottom and hand-tighten with 5mm hex bit on top until snug. Do not over-torque. Hold the 5mm hex bit in place for the next step.
  4. Fasten threads with 10mm lock nut and hand-tighten until snug. Do not over-torque.
  5. Adjust a set screw on the inside of the lever, if necessary.
Left-over parts
  1. The old brake lever assembly.

Faulty Ignition Switch

Symptom
The motorcycle loses all power while making a sharp turn to the right.
Discussions
Sharp turn - Zero goes dead
12V wiring issues
Finding
It was the ignition switch wires broken inside the switch.
Troubleshooting
Take off the headlight and see if a right hand turn stretches the ignition wires tight.
There is only 2 screws holding on the ignition switch and the switch comes away from the key lock part.
In one case, a cable tied too close to the ignition switch, which flexed the cable too much over a short distance.
Recommendations
Pry open (from the key lock) and re-solder the ignition switch.
Fill the bottom part with silicon sealant to stop it from flexing at the soldered joins so it won't happen again.