If any is worn down to the service limit, replace the brush assy.
Starter Motor Brush Length [B] Standard: 12.05 mm (0.4744 in.) Service Limit: 6.55 mm (0.258 in.)

Starter Motor Assembly
Commutator Cleaning and InspectionESD (Electronic Steering Damper) ECU Error (Service Code E3b, ZX1000JD/KD)
If this service code appears, check that the following parts
are correctly.
Crankshaft Sensor
Gear Position Switch
Starter Lockout Switch
Main Throttle Sensor
Rear Wheel Rotation Sensor
If these parts are normal, check the ESD ECU for its
ground and power supply (see ESD ECU Power Supply
...
Starting the Engine
Check that the engine stop switch is
in the
position.
A. Engine Stop Switch
B. Starter Button
Turn the ignition key to “ON”.
Make sure the transmission is in neutral.
A. Neutral Indicator Light
B. Ignition Switch
C. “ON” position
NOTE
The motorcycle is equipped w ...
Brake Light Switches
When either the front or rear brake is
applied, the brake light goes on. The
front brake light switch requires no adjustment,
but the rear brake light switch
should be adjusted in accordance with
the Periodic Maintenance Chart.
Inspection
Turn the ignition key to “ON”.
The brake ligh ...