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 InspectionHandlebar Installation
Apply a non-permanent locking agent to the threads of
the handlebar positioning bolts and tighten them.
Torque - Handlebar Positioning Bolts: 9.8 N·m (1.0 kgf·m,
87 in·lb)
Install the steering stem head with handlebars.
Install the washer [A] and steering stem head nut [B].
Tighten:
...
Master Cylinder Inspection (Visual Inspection)
Remove the master cylinders (see Front/Rear Master
Cylinder Removal).
Disassemble the front and rear master cylinders (see
Master Cylinder Rubber Parts Replacement in the Periodic
Maintenance chapter).
Check that there are no scratches, rust or pitting on the
inner wall [A] of each ma ...
Oil Pump Installation
Install the outer rotor [A] into the crankcase.
Assemble:
Oil (Water) Pump Shaft [B]
Pin [C]
Inner Rotor [D]
To prevent dropping, apply grease to the pin.
Install the inner rotor assembly into the crankcase.
Fit the slot [E] onto the projection [F].
Replace the O-ring [A ...