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 InspectionCylinder Head Cover Installation
Replace the cylinder head cover gasket [A] with a new
one
Using a high flash-point solvent, clean off any oil or dirt
that may be on the silicone sealant coating area. Dry
them with a clean cloth.
Apply silicone sealant [B] to the cylinder head as shown
in the figure.
Sealant - Li ...
Wheel Bearing Damage Inspection
Raise the front wheel off the ground with the jack (see
Front Wheel Removal in the Wheels/Tires chapter).
Special Tools - Jack: 57001-1238
Jack Attachment: 57001-1608
Turn the handlebar all the way to the right or left.
Inspect the roughness of the front wheel bearing by moving
[A] ...
Camshaft Chain Tensioner Installation
Replace the O-ring [A] with a new one.
Apply grease to the new O-ring.
Release the stopper [B] and push the push rod [C] into the
interior of the tensioner body [D] so that the position of the
push rod is 3 or 4 notches [E] as shown in the figure.
Install the tensioner body so that the ...