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 InspectionRear Sprocket Removal
Remove the rear wheel (see Rear Wheel Removal in the
Wheels/Tires chapter).
NOTICE
Do not lay the wheel on the ground with the disc
facing down. This can damage or warp the disc.
Place blocks under the wheel so that the disc does
not touch the ground.
Remove:
Rear Sprocket Nu ...
Radiator and Radiator Fan Removal
Remove:
Upper Fairing Assembly (see Upper Fairing Assembly
Removal in the Frame chapter)
Coolant (Drain, see Coolant Change in the Periodic
Maintenance chapter)
Air Cleaner Housing (see Air Cleaner Housing Removal
in the Fuel System (DFI) chapter)
Coolant Reserve Tank (see Coolant R ...
Piston Ring Thickness Inspection
Measure the piston ring thickness.
Use the micrometer to measure at several points around
the ring.
Piston Ring Thickness
Standard:
Top [A] 0.77 0.79 mm (0.0303
0.0311 in.)
Second [B] 0.78 0.79 mm
(0.0307 0.0311 in.)
Service Limit:
Top 0.70 mm (0.0276 in.)
Second 0.71 mm (0.0280 ...