If the teeth are worn as illustrated, replace the sprocket, and inspect the drive chain wear (see Drive Chain Wear Inspection in the Periodic Maintenance chapter).
Worn Tooth (Engine Sprocket) [A] Worn Tooth (Rear Sprocket) [B] Direction of Rotation [C]
NOTE
If a sprocket requires replacement, the chain is probably worn also. When replacing a sprocket, inspect the chain.

Coupling Damper Inspection
Rear Sprocket Warp InspectionDFI System Troubleshooting Guide
NOTE
This is not an exhaustive list, giving every possible cause for each
problem listed. It is meant
simply as a rough guide to assist the troubleshooting for some of the more
common difficulties in
DFI system.
The ECU may be involved in the DFI electrical and ignition system
tro ...
ESD (Electronic Steering Damper) ECU Error (Service Code E3b, ZX1000JD/KD)
If this service code appears, check that the following parts
are correctly.
Crankshaft Sensor
Gear Position Switch
Starter Lockout Switch
Main Throttle Sensor
Rear Wheel Rotation Sensor
If these parts are normal, check the ESD ECU for its
ground and power supply (see ESD ECU Power Supply
...
Coupling Bearing Installation
Replace the bearing with a new one.
Press in the bearing [A] until it is bottomed.
Special Tool - Bearing Driver Set [B]: 57001-1129
Pack the bearing with high-temperature grease.
Replace the circlip with a new one.
Special Tool - Inside Circlip Pliers: 57001-143
Replace the grease se ...