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 InspectionSpecial Tools and Sealant
Oil Pressure Gauge, 10 kgf/cm²:
57001-164
Oil Pressure Gauge Adapter, PT3/8:
57001-1233
Outside Circlip Pliers:
57001-144
Liquid Gasket, TB1211:
56019-120
...
Stem, Stem Bearing Removal
Remove:
Upper Fairing Assembly (see Upper Fairing Assembly
Removal in the Frame chapter)
Front Fender (see Front Fender Removal in the Frame
chapter)
Front Wheel (see Front Wheel Removal in the
Wheels/Tires chapter)
Steering Stem Head with Handlebars (see Handlebar
Removal)
Fron ...
Refreshing Charge
Remove the battery (see Battery Removal).
Do refresh charge by following method according to the
battery terminal voltage.
WARNINGThis battery is sealed type. Charge with
current and
time as stated below.
Terminal Voltage: 12.0 12.7
V
Standard Charge (see following ...