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 DiscThrottle Body Assy Removal
WARNINGGasoline is extremely flammable and can be
explosive
under certain conditions, creating the
potential for serious burns. Make sure the area is
well-ventilated and free from any source of flame
or sparks; this includes any appliance with a pilot
light. Do not smoke. T ...
Stick Coil Input Voltage Inspection
NOTE
Be sure the battery is fully charged.
Turn the ignition switch to OFF.
Remove the ECU (see ECU Removal in the Fuel System
(DFI) chapter).
Do not disconnect the ECU connectors.
Connect a digital meter [A] to the connector [B] with the
needle adapter set.
Special Tool - N ...
Sport-kawasaki traction control (s-ktrc)
S-KTRC is an intelligent system that
calculates the slip level of the rear
wheel (wheelspin) and is suitable for
sports riding conditions. S-KTRC is
designed to function on public roads.
Acceleration may be delayed under
certain circumstances depending on
road conditions. S-KTRC cannot resp ...