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 DiscWater Pump Housing Disassembly
NOTICE
Do not damage the hole wall of the water pump
housing.
Insert a bar [A] into the pump housing [B], and hammer
evenly around the circumference of the mechanical seal
bottom [C].
Take the oil seal [A] out of the housing [B] with a hook [C].
...
For Secondary Fuel Injectors
Remove the fuel tank (see Fuel Tank Removal).
Disconnect the secondary fuel injector connector [A].
Connect a digitalmeter to the terminals in each secondary
fuel injector [A].
Measure the secondary fuel injector resistance.
Secondary Fuel Injector Resistance
Standard: Abo ...
Oil Cooler Installation
Replace the O-ring [A] with a new one.
Apply grease to the new O-ring.
Install the water hoses and hose clamps [A] as shown in
the figure.
Water Hose (About 300 mm, 11.8 in.) [B]
Water Hose (About 130 mm, 5.1 in.) [C]
Yellow Paint [D]
Tighten:
Torque - Water Hose Clamp S ...