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 InspectionClutch
Clutch Operation Inspection
Pull the clutch lever just enough to take up the free play
[A].
Measure the gap between the lever and the lever holder.
If the gap is too wide, the clutch may not release fully. If
the gap is too narrow, the clutch may not engage fully. In
either case, adjust ...
Check 3-3: High Beam Indicator Light (LED) Inspection
Connect the leads in the same circuit as Check 3-2.
Connect the terminal [7] to the battery (+) terminal.
Check that the high beam indicator light (LED) [A] goes
on.
If the indicator light does not go on, replace the meter unit.
...
Crankshaft Sensor Peak Voltage Inspection
Refer to the Crankshaft Sensor Peak Voltage Inspection
in the Electrical System chapter.
If the reading is within the standard, remove the ECU and
check the wiring for continuity between harness connectors.
Special Tool - Hand Tester: 57001-1394
Disconnect the ECU and sensor connector ...