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 DiscCylinder (Upper Crankcase) Wear Inspection
Split the crankcase (see Crankcase Splitting).
Remove the pistons (see Piston Removal).
Assemble the cylinder (upper crankcase) [A], the cylinder
head [B] and the cylinder head gasket [C].
Tighten the cylinder head bolts (see Cylinder Head Installation
in the Engine Top End chapter).
...
Rear Turn Signal Light Bulb Replacement
Remove the upper seat cover (see Seat Cover Removal
in the Frame chapter).
Disconnect the tail/brake light connector [A].
Turn the socket [A] counterclockwise and remove the
socket together with the bulb.
Push and turn the turn signal light bulb [A] counterclockwise
an ...
Steering Damper Removal
ZX1000JC/KC
Remove:
Steering Damper Mounting Bolts (TORX Bolts) [A]
Washer [B]
Washer and Collar [C]
Steering Damper [D]
ZX1000JD/KD
Remove:
Clamp [A]
Connector [B] (Disconnect)
Steering Damper Mounting Bolts (TORX Bolts) [C]
Washer [D]
Washer and Collar [E]
Elect ...