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 InspectionThermostat Installation
Replace the O-rings [A] with new ones, and apply grease
to them.
Assemble:
O-rings
Thermostat Housing [B]
Thermostat [C]
Thermostat Cap [D]
Install the thermostat [A] in the housing so that the air
bleeder hole [B] is on top.
Tighten:
Torque - Thermostat Cap Bolts: 5.9 N ...
Moving Off
Check that the side stand is up.
Pull in the clutch lever.
Shift into 1st gear.
Open the throttle a little, and start to
let out the clutch lever very slowly.
As the clutch starts to engage, open
the throttle a littlemore, giving the engine
just enough fuel to keep it from
stallin ...
Valve Guide Removal
Remove:
Valve (see Valve Removal)
Oil Seal
Spring Seat
Heat the area around the valve guide to 120
150°C (248
302°F), and hammer lightly on
the valve guide arbor [A]
to remove the guide from the top of the head.
NOTICE
Do not heat the cylinder head with a torch. This ...