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 InspectionWheel Inspection
Raise the front/rear wheel off the ground.
Special Tools - Jack: 57001-1238
Jack Attachment: 57001-1608
Spin the wheel lightly, and check for roughness or binding.
If roughness or binding is found, replace the hub bearings
(see Hub Bearing Removal/Installation).
Inspect the wh ...
Air Suction Valve Inspection
Remove the air suction valve (see Air Suction Valve Removal).
Visually inspect the reeds [A] for cracks, folds, warps,
heat damage or other damage.
If there is any doubt as to the condition of the reeds, replace
the air suction valve as an assembly.
Check the reed contact areas [B] of ...
Balance Weight Installation
Check if the weight portion has any play on the blade [A]
and clip [B].
If it does, discard it.
WARNINGUnbalanced wheels can create an unsafe
riding
condition. If the balance weight has any play on
the rib of the rim, the blade and/or clip have been
stretched. Replace th ...