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 DiscBrakes
Brake Wear Inspection
Inspect the brakes for wear. For each
front and rear disc brake caliper, if the
thickness of either pad is less than
1 mm (0.04 in.), replace both pads
in the caliper as a set. Pad replacement
should be done by an authorized
Kawasaki dealer.
A. Lining Thickness
B. ...
Wheel Alignment Inspection
Check that the notch [A] on the alignment indicator [B]
aligns with the same swingarm mark or position [C] that
the other side alignment indicator notch aligns with.
If they do not, adjust the chain slack and align the wheel
alignment (see Drive Chain Slack Adjustment).
NOTE
Wheel align ...
Ignition System
WARNINGThe ignition system produces extremely
high voltage.
Do not touch the spark plug, ignition coil or ignition
coil lead while the engine is running, or you
could receive a severe electrical shock.
NOTICE
Do not disconnect the battery cables or any other
electrical ...