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 InspectionSolenoid Valve Inspection (Service Code b 13, b 14, b 17, b 18)
The solenoid valve is built in the KIBS Hydraulic Unit [A].
Therefore the solenoid valve cannot be checked directly.
Perform the Pre-Diagnosis Inspection 1 and 2 (see Inquiries
to Rider in the Brakes chapter).
If any of these service codes appears even if all checks
are ended, replace t ...
Water Temperature Sensor Inspection
Remove the water temperature sensor (see Water Temperature
Sensor Removal/Installation in the Fuel System
(DFI) chapter).
Suspend the sensor [A] in a container of coolant so that
the temperature-sensing projection [C] is submerged.
Suspend an accurate thermometer [B] with temperature
...
Armature Inspection
Using the × 1 Ω hand tester range, measure the resistance
between any two commutator segments [A].
Special Tool - Hand Tester: 57001-1394
If there is a high resistance or no reading (∞) between any
two segments, a winding is open and the starter motor
must be replaced.
...