If the measurement is under service limit, replace the piston.

Piston Diameter
Standard: 75.959
75.974 mm
(2.9905
2.9911 in.)
Service Limit: 75.81 mm (2.985 in.)
Cylinder (Upper Crankcase) Wear Inspection
Piston Ring, Piston Ring Groove Wear InspectionExploded 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
...
Premuffler Chamber Installation
Replace the premuffler chamber gasket [A] with a new
one.
Install the premuffler chamber gasket to the premuffler
chamber [B] until it is bottomed so that the chamfer side
faces exhaust pipe [C].
Install the exhaust pipe clamp [D] as shown in the figure.
Insert the projection [E] into ...
Starter Relay Inspection
Remove the front seat (see Front Seat Removal in the
Frame chapter).
Remove the battery negative (–) cable from the battery
negative (–) terminal (see Battery Removal).
Take the starter relay [A] off the rear fender.
Remove the cover [B].
Remove:
Starter Motor Cable [A] ...