If they show any damage, replace it.

Caliper Fluid Seal Damage
Caliper Piston and Cylinder DamageOutline
When a problem occurs with DFI system, the warning indicator
light (LED) [A] and FI warning symbol [B] goes on
to alert the rider. In addition, the condition of the problem is
stored in the memory of the ECU. For models equipped with
an immobilizer system, the warning indicator light (LED)
and ...
ZX1000JC /KC
Models
1. Run the fuse box 2 lead in front of the rib for the fuse box 2.
2. Seat Lock Cable
3. Hook the licence plate light lead and the left turn signal light lead on
the projection of the tool
kit case.
4. Rib for Fuse Box 2
5. Run the starter relay lead in back of the rib for the fuse box 2 ...
Starter Motor Disassembly
Remove the starter motor (see Starter Motor Removal).
Take off the starter motor through bolts [A] and remove
the both end covers [B].
Pull out the armature [A] out of the yoke [B].
NOTE
Do not remove the circlip [C] from the shaft.
Remove the starter motor terminal lock ...