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 InspectionCoolant Level Inspection
Situate the motorcycle so that it is
perpendicular to the ground.
Check the coolant level through the
coolant level gauge on the reserve
tank located to the left of the engine.
The coolant level should be between
the “F” (Full) and “L” (Low) level lines.
A. Reserve Ta ...
Brake Line Bleeding
The brake fluid has a very low compression coefficient so
that almost all the movement of the brake lever or pedal
is transmitted directly to the caliper for braking action. Air,
however, is easily compressed. When air enters the brake
lines, brake lever or pedal movement will be partially used
...
Piston Removal
Remove:
Crankshaft (see Crankshaft Removal)
Remove the piston together with the connecting rod to the
cylinder head side.
NOTICE
Discard the connecting rod bolts and nuts. To prevent
damage to the crankpin surfaces, do not allow
the connecting rod bolts to bump against the
crankpins. ...