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 InspectionSpecial Tools and Sealant
Hand Tester:
57001-1394
Flywheel Puller Assembly, M38 × 1.5/M35 × 1.5:
57001-1405
Peak Voltage Adapter:
57001-1415
Lead Wire - Peak Voltage Adapter:
57001-1449
Key Registration Unit:
57001-1582
Grip:
57001-1591
Flywheel & Pulley Holder:
57001-1605
Rotor Holder:
...
High Speed Compression Damping Adjustment
Turn the high speed compression
damping force adjuster clockwise to
increase damping force or counterclockwise
to decrease it.
NOTICE
Do not turn the compression
damping force adjuster beyond
the fully seated position or the
adjusting mechanism may be
damaged.
A. Compression Da ...
Location of parts
Clutch Lever
Left Handlebar Switches
Rebound Damping Force Adjuster
(Front Fork)
Compression damping force adjuster
(Front Fork)
Meter Instruments
Brake Fluid Reservoir (Front)
Right Handlebar Switches
Front Brake Lever
Throttle Grip
Ignition Switch/Steering Lock
Elect ...