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 DiscCompression Damping Force Adjustment
There are two adjustments you can make to the compression
damping force.
High Speed Compression Damping Adjuster [A]
Low Speed Compression Damping Adjuster [B]
To adjust the high speed compression damping force, turn
the outside damping adjuster with a wrench to the desired
position ...
Drive Chain Slack Inspection
NOTE
Check the slack with the motorcycle setting on its sidestand.
Clean the chain if it is dirty, and lubricate it if it appears
dry.
Check the wheel alignment (see Wheel Alignment Inspection).
Rotate the rear wheel to find the position where the chain
is tightest.
Measure the ver ...
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 ...