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 DiscIntake Air Pressure Sensor #2 Removal
NOTICE
Never drop the intake air pressure sensor #2 especially
on a hard surface. Such a shock to the sensor
can damage it.
Remove:
Air Cleaner Housing (see Air Cleaner Housing Removal
in the Fuel System (DFI) chapter)
Intake Air Pressure Sensor #2 Connector [A]
Remove the intake air ...
Overview
Kawasaki Intelligent anti-lock Brake System (KIBS) offers enhanced braking
stability (ABS performance
equivalent to the current model) to supersportmodels, which pitch more than most
motorcycles
and also offers high-precision front and rear brake pressure control
(high-precision ABS) for spo ...
Vehicle-down Sensor Output Voltage Inspection
Remove the vehicle-down sensor.
Connect the measuring adapter [A] to the vehicle-down
sensor connectors as shown in the figure.
Special Tool - Measuring Adapter: 57001-1700
Main Harness [B]
Vehicle-down Sensor [C]
Connect a digital meter [D] to the measuring adapter
leads.
V ...