If there are notches worn into the splines, replace the sub clutch hub. Also, replace the steel plates if their teeth are damaged.

Clutch Housing Finger Inspection
Damper Cam InspectionSidestand Removal
Raise the rear wheel off the ground with the stand [A].
Remove:
Sidestand Switch Bolt [A]
Sidestand Switch [B]
Remove:
Spring [A]
Sidestand Nut [B]
Sidestand Bolt [C]
Sidestand [D]
...
Coolant Reserve Tank Installation
Install the following to the coolant reserve tank [A].
Pad [B]
Gasket [C]
Cap [D]
Collar [E]
Install the coolant reserve tank and tighten the bolt [F].
Run the hoses correctly (see Cable,Wire, and Hose Routing
section in the Appendix chapter).
Fill the coolant reserve tank with ...
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 ...