If a master cylinder or piston shows any damage, replace them.

If a cup is worn, damaged softened (rotted), or swollen, the piston assembly should be replaced to renew the cups.
If fluid leakage is noted at the brake lever, the piston assembly should be replaced to renew the cups.
If they are damaged, replace them.
If the springs are damaged, replace them.
If the relief port becomes plugged, the brake pads will drag on the disc. Blow the ports clean with compressed air.
Front Master Cylinder [I] Rear Master Cylinder [J]

Rear Master Cylinder Installation
Brake DiscShift Fork/Gear Groove Wear Inspection
Measure the thickness of the shift fork ears [A], and measure
the width [B] of the gear grooves.
If the thickness of a shift fork ear is less than the service
limit, the shift fork must be replaced.
Shift Fork Ear Thickness
Standard: 5.7 6.0 mm (0.224
0.236 in.)
Service Limit: 5.6 mm ...
Spark Plugs
The standard spark plug is shown in
the table. The spark plugs should be
replaced in accordance with the Periodic
Maintenance Chart.
Spark plug removal should be done
only by a competent mechanic following
the instructions in the Service Manual.
Spark Plug
A. Plug Gap ...
Damping Force Adjustment (
ZX1000JC/KC)
To adjust the damping force, turn the damping adjuster
[A] until you feel a click.
The standard adjuster setting is the 18th click from the
1st of the fully clockwise position. If the damping feels too
soft or too stiff, adjust it in accordance with the following
table.
Damping Force Adj ...