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 InspectionFront Fork Installation (Each Fork Leg)
Install the fork so that the top plug end [A] as shown in the
figure.
11 mm (0.43 in.) [B]
Steering Stem Head [C]
Tighten:
Torque - Front Fork Clamp Bolts (Lower): 23 N·m (2.3
kgf·m, 17 ft·lb)
NOTE
Tighten the two lower front fork clamp bolts alternately
two times to ensur ...
KIBS Servicing Precautions
There are a number of important precautions that should
be followed servicing the KIBS.
This KIBS is designed to be used with a 12 V sealed battery
as its power source. Do not use any other battery
except for a 12 V sealed battery as a power source.
Do not reverse the battery cable connec ...
Subthrottle Sensor Output Voltage Inspection
Measure the output voltage at the subthrottle sensor in
the same way as input voltage inspection, note the following.
Disconnect the subthrottle sensor connector and connect
the setting adapter [A] between these connectors.
Special Tool - Throttle Sensor Setting Adapter: 57001
-1538
...