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 #1 Output Voltage Inspection
Measure the output voltage at the intake air pressure sensor
#1 in the same way as input voltage inspection, note
the following.
Disconnect the intake air pressure sensor #1 connector
and connect the measuring adapter [A] between these
connectors.
[B] Main Harness
[C] Intake Air Pressu ...
DFI System Wiring Diagram (KIBS Equipped Models)
1. Air Intake Solenoid Valve (Other than US, CA and CAL Models)
2. Engine Stop Switch
3. Starter Button
4. Air Switching Valve
5. Stick Coil #1, #2, #3, #4
6. Spark Plugs
7. Intake Air Temperature Sensor
8. Crankshaft Sensor
9. Secondary Fuel Injector #1
10. Secondary Fuel Injector #2
...
What is a Limited Warranty?
The most important thing to know about your warranty is that it protects you
from manufacturing defects in material or workmanship during the warranty
period.
You can find the warranty period in the Kawasaki Limited Warranty Certificate
your Kawasaki dealer provided to you at the time of sale ...