If they show any damage, replace it.

Caliper Fluid Seal Damage
Caliper Piston and Cylinder DamageMode-switching
Depress the S-KTRC button on the left handlebar switch
to change the mode. The mode can be changed only when
the throttle grip is closed completely.
The S-KTRC OFF can be selected only when the motorcycle
is at a stop. Changing to mode 1 from S-KTRC OFF
is possible while riding.
NOTE
...
Special Tools
Bearing Driver Set:
57001-1129
Jack:
57001-1238
Bearing Remover Head, 25 × 28:
57001-1346
Bearing Remover Shaft, 13:
57001-1377
Jack Attachment:
57001-1608 ...
Air Cleaner Housing Installation
For ZX1000JD/KD, be sure to install the pad [A].
Install the clamp bolt heads [A] inside as shown in the
figure.
Install the air cleaner housing on the throttle body assy.
Push in the ducts [B] touch the stoppers [C] of the throttle
body.
Be sure the hoses are routed correctly ...