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 InspectionCheck 2-2: Fuel Level Warning Inspection
Remove:
Fuel Tank (see Fuel Tank Removal in the Fuel System
(DFI) chapter)
Connect the resistor(s) [A] (about 50 to 100 Ω) between
the fuel pump connector terminal [B] of the main harness
side and the battery negative (–) terminal [C] as shown.
Turn the ignition switch ...
Crankshaft Sensor Peak Voltage Inspection
NOTE
Be sure the battery is fully charged.
Using the peak voltage adapter [A] is more reliable way
to determine the condition of the crankshaft sensor than
crankshaft sensor internal resistance measurements.
Disconnect the crankshaft sensor lead connector (see
Crankshaft Sensor ...
Rear Frame Front Removal
Remove:
Rear Frame Rear (see Rear Frame Rear Removal)
Rear Fender Front (see Rear Fender Front Removal)
Rear Footpeg Bracket Bolts [A]
Rear Footpeg Bracket [B]
Rear Frame Front Bolts [C]
Left Rear Frame Front [D]
Remove:
Rear Footpeg Bracket Bolts [A]
Rear Footpeg Bracke ...