If they appear damaged or deteriorated, replace them.

Balancer Adjustment
Torque LimiterStick Coil Removal
Remove the air cleaner housing (see Air Cleaner Housing
Removal in the Fuel System (DFI) chapter).
Disconnect the stick coil connectors [A].
Pull out the stick coils [B] upward.
First, turn the stick coil by 90 degrees, and then pull it out
by twisting the coil head to the left and righ ...
Steering Damper Oil Leak Inspection
Visually inspect the steering damper [A] for oil leakage.
If the oil leakage is found on it, replace the steering
damper with a new one (see Steering Damper Removal/
Installation in the Steering chapter).
ZX1000JD/KD [B]
...
Commutator Cleaning and Inspection
Clean the metallic debris off the between commutator
segments [A].
NOTE
Do not use emery or sand paper on the commutator.
Check the commutator for damage or abnormal wear.
Replace the starter motor with a new one if there is any
damage or wear.
Visually inspect the commutato ...