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 InspectionSteering Play Inspection
Remove the lower fairings (see Lower Fairing Removal in
the Frame chapter).
Raise the front wheel off the ground with the jack.
Special Tools - Jack: 57001-1238
Jack Attachment: 57001-1608
With the front wheel pointing straight ahead, alternately
tap each end of the handlebar. The f ...
Front Wheel Removal
Remove:
Front Caliper Mounting Bolts [A] (Both Sides)
Front Caliper [B] (Both Sides)
Loosen:
Front Axle Clamp Bolts [A] (Right Side)
Front Axle [B]
Remove the lower fairings (see Lower Fairing Removal in
the Frame chapter).
Raise the front wheel off the ground.
...
Passenger’s Seat Removal
Remove the passenger’s seat by inserting
the ignition key into the seat
lock, and turning it clockwise.
A. Seat Lock
B. Ignition Key
C. Passenger’s seat
D. Pull up
NOTE
When removing the passenger’s
seat, pull it up while turning the key. ...