Replace any damaged gears or gears with excessively worn dogs or dog holes.

Shift Fork Guide Pin/Drum Groove Wear InspectionIgnition Switch Replacement
Remove:
Air Cleaner Housing (see Air Cleaner Housing Removal
in the Fuel System (DFI) chapter)
Disconnect the lead connectors [A].
Remove:
Steering Stem Head (see Stem, Stem Bearing Removal
in the Steering chapter)
Using a small chisel or punch [A], turn out the Torx bolts.
...
Swingarm Installation
Visually inspect the chain guide [A].
Replace the chain guide if it shows any signs of abnormal
wear or damage.
Apply a non-permanent locking agent to the threads of
the chain guide bolt [B].
Apply plenty of grease to the lip of the oil seals [A].
Be sure to install the oil seals ...
Inquiries to Rider
Each rider reacts to problems in different ways, so it is important to
confirm what kind of condition
the rider is dissatisfied with.
Try to find out exactly what problem occurs under exactly what
conditions by asking the rider; knowing
this information may help you reproduce the prob ...