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 InspectionFront Fender Removal
Remove:
Bolts [A] with Washers (Both Sides)
Reflectors (Both Sides, US, CA, CAL and AU Models)
Front Fender [B]
Take the brake hose off the clamp [C] (both sides).
Front Fender Installation
Apply a non-permanent locking agent to the front fender
mounting bolts.
Tighten:
...
Spark Plugs
The standard spark plug is shown in
the table. The spark plugs should be
replaced in accordance with the Periodic
Maintenance Chart.
Spark plug removal should be done
only by a competent mechanic following
the instructions in the Service Manual.
Spark Plug
A. Plug Gap ...
Rear Fender Front Installation
Installation is the reverse of removal. Note the following.
Run the harness, cables and leads correctly (see Cable,
Wire, and Hose Routing section in the Appendix chapter).
When installing the clamp [A] on the rear fender front [B],
install it so that the clamp positions at near the ...