Z-Force Motor/Sounds

The Z-Force Motor family has many characteristic sounds worth minding and distinguishing.

Because the motor is so quiet overall, anomolous sounds should be more notable, from say bearings, sprockets, or the belt.

The motor on 2013+ models makes a white noise sound at very slow speeds when rotated (by the wheels or shaft).

This is also described as a "whirring sound".

This is alluded to by the term "cogging".

This is normal as long as it sounds like white noise and occurs as described below.

The noise should only occur while the motor is rotated by external input (pushing the bike around or rotating the shaft).
The noise should not while under power (when the motor is driving its own rotation).
The bike should gently resist being pushed while the noise is audible.

The direct cause is the controller applying a white noise field to the motor at very slow speeds.
At least one connected battery's contactor must have been engaged for this to occur.
This can occur while keyed on, or while charging.

There are no detrimental effects, when the sound occurs by design.
The purpose is for the controller to detect and maintain precise knowledge of the motor's rotor angle.
This ensures that, if the throttle demands operation, the controller will apply the field correctly to the rotor.
You may infer that at least one contactor is engaged to power the controller.
If the bike is keyed on, you may infer that the motorcycle should be ready to drive.
(aside from the kickstand and kill switch safety interlocks).

While moving, the motor tends to make a solid smooth tone resonant with the motor's rotational speed.

The motor shaft bearings are likely the primary generator of this resonant noise.

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