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 InspectionOil Level Inspection
Check that the engine oil level is between the upper [A]
and lower [B] levels in the gauge.
NOTE
Situate the motorcycle so that it is perpendicular to the
ground.
If the motorcycle has just been used, wait several minutes
for all the oil to drain down.
If the oil has just been changed, ...
Spark Plug Replacement
Remove the stick coils (see Stick Coil Removal in the
Electrical System chapter).
Remove the spark plugs using the 16 mm (0.63 in.) plug
wrench [A] vertically.
Replace the spark plug with new ones.
Standard Spark Plug
Type: NGK CR9EIA-9
Insert the spark plug vertically into the sp ...
Engine Installation
Apply molybdenum disulfide grease to the threads of the
adjusting collars [A].
Install the adjusting collars to crankcase backside until
end of the threads.
Install the adjusting collar [A] to the frame until end of the
threads.
Replace the engine mounting nuts with ne ...