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 InspectionStarter Motor Installation
NOTICE
Do not tap the starter motor shaft or body. Tapping
the shaft or body could damage the motor.
Clean the starter motor legs [A] and crankcase where the
starter motor is ground.
Replace the O-ring [A] with a new one.
Apply grease to the new O-ring.
Tighten:
Torque - Starter ...
Exploded View
11. ZX1000JD/KD
AD: Apply adhesive.
AL: Tighten the two clamp bolts alternately two times to ensure even tightening
torque.
G: Apply grease.
L: Apply a non-permanent locking agent.
Specifications
...
Starter Clutch Assembly
Install the one-way clutch [A] to the driven gear.
Face the circlip side of the one-way clutch to inside.
Install the new snap ring [B] to the one-way clutch.
Install the drive gear [C] while turn it counterclockwise [D].
Apply molybdenum disulfide oil solution to the needle
bearing ...