Common Problems

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This is a basic troubleshooting guide, and also an indication that the symptom you're seeing is relatively common and has been thought about, often with some basic solutions.

Behavior in wet weather

Avoid pressure-washing. Weatherproofing is much less effective against high pressure.

There are a few particularities of Zeros when they're exposed to excess moisture, particularly in heavy rain or after washing the bike.

Display Flicker

The dashboard can often be sensitive in wet conditions. Occasionally it will display flickering or incorrect light indicators. This will not affect normal operation of the bike and functionality should return to normal after drying out.

Applying electrical insulating grease to connections might alleviate this.

Groan Sound

The belt in wet conditions will often make a pronounced new noise from when it's in dry conditions.

This groaning noise has been called many things from a Tie fighter to a water buffalo.
It is completely normal and causes no ill effect on the bike, and will go away again when dry.
Silicone Spray Suggestion
Light application of a silicone spray to the motor shaft at the front sprocket that is safe for belt material should make it go away for months.
NOTE: Make sure the spray doesn't have any petroleum distillates that will eat the belt materials.
This thread describing a loud buzzing sound on acceleration has audio samples and discussion about how it occurs.
Encoder Accuracy Hypothesis
There is a strong perception that the sound comes from the belt, but also an impression that the encoder sensors inside the motor lose accuracy in high humidity.
This would make the controller think the motor is in a slightly different position, then send the wrong/displaced field to the motor, which would result in an oscillation.
The motor might be driving the belt to resonate in this case.
For this reason, where to apply the silicone spray should be near the front sprocket to protect moisture from entering the motor housing.

Loss of Traction

The high torque of the SR and DSR can be an issue if you are not careful, especially on surfaces right after rain starts for the first times after a dry spell, as accumulated oil from vehicles has floated out of the pavement but not been washed away.

In an intersection, the rear tire may slip above a certain torque, particularly when starting from a stop into a turn.
At speed, the rear tire may slip when leaning into a turn or going over a bumpy and oily surface, initiating a fishtail.
To recover, ease off the throttle very slowly while transferring weight from the seat to the footpegs, while using the handlebars loosely to prevent initiating oversteer.
If it rains after a long dry spell, Eco mode is worth trying because the torque roll-on rate is really low which means the onset of a slip can be recovered from without overreacting.

Splash Protection

Zero motorcycle models have a rear wheel splash guard that protects the motor and the lower electrical areas under the seat, but the wheel can fling plenty of rain and mud onto the tail and on the back of the rider.

OEM Top Rack
A mudguard

Loss of Power

The accessory charging port comes with a rubber boot/cover.

Recommend: Leave it on when riding.
If moisture gets to the signal pins, the motorcycle may turn off due to the battery detecting a short and opening the contactors.
This circuit is low voltage so not dangerous, but loss of power while riding can be dangerous.

If the motorcycle cuts out in the rain or shortly after, check whether the connector is covered properly and try to dry it out (pull off the boot and shake it free of moisture) while the bike is keyed off.

If the motorcycle exhibits cutouts in the rain, apply dielectric grease to vulnerable connections to minimize the chance of shorting or the appearance of a short.

Power Cutout Failure

If the bike does not turn off when the key is turned off, check for moisture around the "ignition" lock.

Loss of Range

  • The majority of range loss is due to the effects of cold weather on the battery.
  • Internal resistance increases in batteries at low temperatures.
  • Rain will exacerbate the problem since thermal transfer will be higher with water contacting the battery case.
  • The official manual has a section for Cold Weather specifically calling out that up to 30% of range might be reduced at 30F ambient temperature.
  • The effect is roughly linear below (say) 45F ambient temperature.
  • The internal resistance of the battery is the primary mechanism for reduced performance.
If full range is required at low temperatures, wrap the battery in a suitable insulating material in cold seasons.
Neoprene at 1/16" thickness has been tested at highway speeds to make a marked difference in battery temperature (but not to an unsafe degree).
Cover the front of the battery primarily and the forward halves of the sides.
Make sure to securely fasten the neoprene so it will not get caught in the front wheel.
Grommeted holes can be used to secure the wrap through the central frame tube and the tank plastics.
A thin (3mm or 1/8") sheet above the battery would also help in cold precipitation.
Masking tape across the front face has also been used effectively.
Warning: Any wrap used to insulate the battery at low temperatures will prevent sufficient cooling for it to operate at normal temperatures. Remove any wrap when operating above 45F.
Advice/Experience via Zee in Northern Ontario
Well this Canuk is a heavy sled (snowmobile) head and lives in northern ontario and owns 2 Zero's 2010MX & 2015FX and rides all year long as long as the roads are clear.
  • The bikes are stored in a non heated garage and it takes full battery awareness and charging smarts to keep everything going all winter.
  • The temperature inside the garage is usually 10C warmer then outside.
  • I automatically plug every bike in after every discharge when the batteries are still warm so the FX is usually fully charged when I start a ride.
  • When I decide to go for a ride and it is -20C outside
    1. I will first go for a 20% discharge were the bike will run like a lame duck.
    2. Then I will put the bike back on charge with extra charger while the batteries are warmed up
    3. When the bike is back at full charge then the bike wakes up a bit but still not at full summer power but enough power to tickle my fancy.
I can't wait for battery technology to advance so I can covert my sled (snowmobile).
  • Also be aware that the battery will shut down with up to 20% power left if you are pulling steady on it in the cold weather :) cheers

Weak power in cold temperatures

From EMF:

> ... higher internal resistance of the battery at colder temperatures causing current limiting, ... It can be a little disconcerting when this happens right as I am trying to overtake slower vehicles.

> You are right and you can even see that in the logs. You'll see entries "discharge current limited (XX%)". That tells you the percentage the power (=battery current) has been limited to, because of the high voltage sag due to higher internal resistance because of the cold. Right behind that you will read a "MinCell" entry, this one tells you which cell was the weakest and caused the limitation and with what voltage.

> The limitation of power is directly related to topspeed, as you need more power the faster you ride.


GFCI Faults

Ground fault circuit isolation outlets detect unequal currents across the hot to neutral prongs.

Zero's onboard charger tends to aggravate these detectors, particularly if paired with another load on the same circuit phase in a household or building.

Recommendation: if GFCI faults occur regularly for you, use a cheater plug to mask the Zero's three-prong plug as a two-prong ungrounded plug, or just break off the grounding prong in the cable plug with a pair of pliers.

Stuck/Warm Charging Cord

From this thread, there's a good explanation of what can cause a power cord to get stuck/fuse.

Most charge cord recommendations focus rightly on wire gauge and length to avoid heating. A stuck cord/plug on the other hand will be due to the connectors fusing together, possibly after years of use, so it's a connection that has deteriorated to the point where it generates its own heat.

If you are using a cord that does not meet Zero's requirements, the cord or particularly the plug may not be rated for the current (12A continuous at least), and will overheat for that reason.
  • Clean the contact prongs on the motorcycle's receptacle. Use something specialized for the purpose.
    Road debris or just dirt on the prongs can increase electrical resistance and produce heat that weakens the cable plug.
  • Try to avoid bending the blades of the male connector whenever possible.
    They should be fairly well annealed brass but they will eventually fatigue.
  • One preference is to have them bent inward slightly.
    That gives a little bit of pressure between the blade and the socket which helps provide a low-resistance connection.
  • Keep an eye on the strain relief on the backside of the connector.
    If you see cracks starting to appear, you might want to replace the cord or at least get a backup so you won't be left without one when it fails.
  • Be sure to always grab the molded part of the connector when disconnecting, rather than yanking on the cord.
    Especially when the cable is warm and soft, that's a great way of pulling it apart.

Charging Errata

Charging light stays on after completion (2017 model year)
"...prior to 2017 models, the green charge indicator did go out once the bike was unplugged. For 2017 though, a component was deleted, so the light stays on until voltage in the circuit bleeds off, or the contactor is closed."
Source: Re: Zero SR 2017. New model startup issues or just my bike? Electric Motorcycle Forum user droidish reports on the charging indicator staying on after completion)

Frame/Body Panels

Prior to 2017, Zero's plastic panels' color is molded-in and will fade with exposure to the sun over a year or two.

The battery casing will also acquire a mild kind of patina over time if left sun-exposed over a very long time.

Front Wheel/Suspension/Steering

Fork Oil Leak

Sometimes the front fork seal can leak because it gets dirty. One recommendation is to keep a handy tool for cleaning it out quickly. SealMate has been recommended but other solutions can be equivalent.

FastAce Left Fork Leak
The FastAce front forks for the 2013 (and possibly 2014) are known to sometimes develop a weep/leak on the bottom of the left tube.
The vaguely-communicated cause is the asymmetric strain of the single brake disc on that side, combined with a lack of compensating setup when installing the tubes.
Zero tends to include this issue under normal warranty coverage, to replace the tubes, if the forks themselves develop the problem less than a year after having installed them.

DS/FX Front Brake Line Obscures Dash

  • The DS and FX have an armored front brake line with ABS wire clipped onto it that runs in front of the handlebars.
  • It usually obscures the ignition but sometimes the lower part of the dash display.
  • 2017 models' design resolves this.

It's okay to re-route the cable or use some strap (zip tie or hook-and-loop) to pull it towards the handlebar to clear up the cockpit.

One reroute method (2015-2016)
  1. Remove the 4 dashboard bolts.
  2. Remove the 2 headlight bolts.
  3. Push dashboard through loop in brake line.
  4. Unplug the 2 headlight wires.
    The main connector is tight; it's easier remove the bulb, but don't touch it.
  5. Put the brake line on other side of headlight wires.
  6. Replace the headlight wires.
  7. Wire-tie the ABS wire plug to the larger plug behind the dashboard, so it doesn't dangle.
  8. Replace the dashboard with 4 bolts.
  9. Observe the arc of the brake line.
    Is it forming too tight an arc? Move it if so.
  10. Turn the handlebar to its extremes, and observe the brake line.
    Is it being pinched, or rubbing against anything sharp? Use zip-ties to hold it away, if so.
  11. Compress the front forks (lean on bike), while moving handlebar to extremes, and observe brake line.
    Is it rubbing against anything sharp?
  12. Repeat until you're satisfied there is no way the brake line is endangered.
  13. Bolt on the headlight.
  14. Perform a final check (turning the handlebars and compressing the forks) for abrasion.
  15. Test drive: go up/down curbs, or otherwise compress / test range of motion.

Rear Wheel/Suspension/Belt

If the rear wheel leaves the surface under acceleration, it can accelerate rapidly, overstressing the belt when landing. Belts have been reported broken, leading some to switch to noisy chains instead. Take care with potholes and speed bumps, it you leave the surface, lay off the throttle to avoid damaging the belt.

Noisy Belt

From this FB post as a method for dealing with belt noises:

I adjusted a squeak out of my belt by fine tuning where the belt rides on the rear sprocket.
  1. Adjust the belt tension screws on the back axle so the belt tracks just barely off the side lip.
    The side lip was rubbing the side of the belt and making noise.
  2. Loosen the axle nut so the tensioners can move the axle freely.
  3. Adjust the belt tension with the sprocket side tensioner and keep the brake disc side even, using the brake side tensioner screw.
  4. Use the alignment notches on each side as a reference.
  5. Then, with the rear wheel off the ground, spin the back wheel by hand.
    Using the accelerator is sketchy and spinning by hand will probably do the job.
  6. Observe where the belt is riding.
  7. Adjust the brake side tensioner a 1/4 turn (or less), in or out, and spin the wheel again. Observe where the belt is tracking.
    As you do this a few times you will see the belt move from side to side.
    When you find the spot where the belt tracks just off off the side lip, and the tension is correct, that is the happy spot!
    That should eliminate some belt noises.
  8. Tighten up the locking screws on the tensioner bolts, and tighten the axle nut when finished.
I am not a motorcycle mechanic, but using the notches for axle location is just not accurate enough for belt tracking.
For a loose chain drive, such alignment is not an issue.

Rear Vibration

Vibration after rear tire replacement

  • Check for wheel balance after a tire replacement. Balancer stands and compensating weights are commonly available; whoever changed the tire should have done this.
  • Check for and fix any belt alignment issues.

Belt Damage

Belts are most commonly damaged by using the throttle in the moment that a wheel becomes airborne, over a bump at speed, say.
If the wheel spins up momentum in the air, regaining traction on landing will jerk the belt, causing a loss of belt teeth or the belt may snap entirely.
Gravel, road debris, or sand can damage or snap the belt if caught between the belt and the sprocket.
Sand seems to be the most sure to destroy a belt; gravel has a lower probability given some basic design protections that should scatter gravel out of or away from the sprocket.
Teeth loss tolerance
Missing belt teeth can be tolerated briefly until a replacement can be made by riding at low torques (easy acceleration, not too high sustained speeds).
The front sprocket has up to 28 total teeth, and only half of those can be in contact with the belt at any given moment, so a continuous sequence of stripped belt teeth might continue up to perhaps 12 but any length of missing teeth is riskier as it gets longer.
The teeth and inner surface of the belt can melt into the front sprocket if the sprocket slides where there are not teeth
If the front sprocket slides, the front sprocket will go fast and it will take out additional teeth as the wheel catches up
Eventually you will have to remove material from the front sprocket or replace it. And eventually the belt will break and you will be unable to climb a San Francisco hill (does this sound oddly specific?)
Scraping out the material with metal can damage the sprocket. Avoid it. A hardwood dowel or a polycarbonate rod, sharpened, is better. Acrylic is too weak.

Brake System

Brake Squeal

Potential noise solution: LocTite Disc Brake Quiet stick applicator for the backs of the pads.

Constant brake squeal on new bikes may go away after bedding the brakes per the OEM manual and then giving the bike a wash.

Regenerative Braking

When starting with a full charge, downhill, with a mode that does regenerative braking, you may feel a pulsing, as the regenerative braking repeatedly engages and then disengages so as to not overcharge. 2015 and newer versions of the firmware appear to soften or eliminate this effect. Using sport mode intentionally for the length of a block appears to be enough to start using regenerative braking.

Regenerative braking is only enabled in the speed range of about 8 mph to 70 mph (could vary slightly depending on model). If you go faster or slower, even in a mode with regeneration enabled, it will not turn on until your speed falls within that range.

When braking, it can be effective to apply the brake lightly, just enough to activate the taillight, well ahead of time. This minimizes brake pad wear while improving range (in Eco mode or Custom mode, depending on regenerative braking settings).

Parking on Hills

Lacking a clutch and transmission, a Zero offers no built-in support for preventing a parked motorcycle from rolling downhill.


  • OEM brake lever lock
  • Double-sided velcro loop.
  • Grip Lock is a security device for locking the throttle and front brake.
  • The 2017 Owner's Manual explicitly describes a Parking Brake accessory and shows how to operate it (paddle on the right handlebar side that operates a rear brake caliper). Presumably it will be available sometime in 2017.


Low SoC

For 2014 and earlier S/DS/SR models, power is reduced below 15% battery charge, and may cut out at or below 10%.

The controller is definitely reducing power to protect the battery when its voltage is reduced.

One point of confusion is why power cuts back before 0%. It may to be due to individual cels being fully discharged too soon. Turning the bike off for a minute and then turning it on may allow using the bike for a few more miles at very slow speeds and power in order to limp home, because the lowest cel should temporarily rebound in voltage enough to satisfy the battery protection logic even though the cell will not produce power and will strongly limit what can be done with the battery until recharged.

Models with fewer battery bricks like the FX will cut back power much sooner near 50% battery charge because each cell has a greater impact on the entire power pack.

2015 models experience this trouble less acutely, and 2016 models seem willing to continue travel at 0% for up to several miles. The implication is that the cells are much more robust in these battery generations, and an abnormally low individual cell is very unlikely.

If there is an emergency need to operate to motorcycle this way, use the battery voltage display in the mobile app to understand how far away you are from the battery being completely unusable.

In any case, running the battery charge this low should be followed immediately by charging to prevent damaging the battery, and it may reduce overall battery lifetime if performed regularly.


After "spirited" riding especially on an SR or a DSR a temperature icon may flash, indicating high temperature. If temperature continues to build it will go solid (p. 4-14 2014 Zero SR owners manual)

On pre-2012 models, it is important to slow down and let the motor and electronics cool as there are no inbuilt protections.

On 2012 and newer Zeros, the controller will automatically reduce phase current as the motor heats up which reduces performance and motor heat. This gets more aggressive as motor heat increases until power is reduced to a point where the motor is shedding heat as fast as it can generate it.

The 2014 and newer SR and DSR motors have higher temperature magnets, and it is normal to see 120+C under spirited riding.

The 2016 SR/DSR/FXS motors (and S/DS motors for 4-brick variants) have an interior permanent magnet design that reduces the heat produced and reduces the stress from heating by distributing the heat generated, so they appear to operate cooler in the same conditions for longer periods of time. It has been said that with an IPM motor, the controller becomes the limiting performance factor.

With rapid highway riding, and rapid charging, can cause battery overheating. It may be difficult to charge (the contactor opens up above 50C). Slowing to 55-60 mph for the last miles before charging is reportedly enough to cool the battery enough to allow rapid charging. Once you are stopped, without airflow on a hot day, it may be difficult to proceed for some time.



On a hot day, or with rapid chargers, the battery may get hot when charging. You can use the app to detect this condition. It is recommended to charge in the shade, when possible, with good ventilation.

A half cover or stretch-cover can help make shade.

Electrical System

Hazard Lights Interfere With Turn Signals

On 2016 models, the turn signals can stop working when the hazard lights are engaged.

While either left or right turn signal are engaged:

  • If you hit the hazard switch while the dash turn signal indicator is off, the circuit will lock out.
    It can only be reset by canceling the turn signal.
  • If you time it so you engage the hazard indicators while the dash turn signal indicator is on, the circuit will work normally.
Hopefully rarely will you need to use the hazard indicators while a turn indicator is engaged.
If you do need this, cancel the turn signal before you hit the flasher button (or you stand a 50% chance of locking up the circuit).
  1. Turn off the hazard lights.
  2. Reset the turn signal.
Blinking switch malfunction

App and Bluetooth

Mobile App Pairing
  1. Ensure the kickstand is down, the run switch is in the Stop position, and the key is in the Off position.
  2. Turn the key to the On position and:
    • For 2014+ models, hold the Mode button for five seconds
    • For 2013 models, toggle the SPORT ECO switch 12 times.
  3. Then select the motorcycle to pair from your device:
    • On Android, select Setup, Available Devices, Scan.
    • On iOS, use the Settings app, select Bluetooth, and scan for new devices.
  4. When Zero Motorcycle appears, pair to it and verify the six digit code.
Mobile App Reconnection
The app's UI is identical for iOS and Android which has some annoying results, because each platform handles Bluetooth connectivity differently.
When the app is disconnected from the device, a dialog will appear offering to use the app in offline mode or visit the settings screen.
On Android, the settings screen can reconnect to the device, whereas on iOS, this feature is not possible.
On iOS, to reconnect, visit the Settings app itself, navigate under bluetooth, and reconnect to the device in the list presented.
Android App ChangeLog (from apkpure)
1.2.8 for Android 2.3.4+
  • Fixed crashes in home screen.
1.3.16 for Android 4.0+
  • Miscellaneous bug fixes and performance enhancements
  • Updated to include 2015 and 2016 model year Zero Motorcycles
  • Enhanced diagnostic reporting via ability to send battery management system (BMS) logs on 2014 model year and later Zero Motorcycles.
1.3.17 for Android 4.0+
  • Miscellaneous bug fixes and performance enhancements
  • Updated to include 2015 and 2016 model year Zero Motorcycles, including the 11kW models
  • Enhanced diagnostic reporting via ability to send battery management system (BMS) logs on 2014 model year and later Zero Motorcycles.
1.4.54 for Android 4.1+
  • Owners of 2017 models can use the Zero Motorcycles app to update their motorcycle’s firmware, saving time, money and service trips
  • Miscellaneous bug fixes and performance enhancements
  • Support for Italian language.
1.4.56 for Android 4.1+
  • Owners of 2017 models can use the Zero Motorcycles app to update their motorcycle’s firmware, saving time, money and service trips
  • Miscellaneous bug fixes and performance enhancements
  • Support for Italian language.
1.4.59 for Android 4.1+
  • Crash fix for pre-5.0 (Lollipop) devices
  • Battery tab should now be quicker to load.