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 DiscOverview
S-KTRC is a highly sophisticated system based on MotoGP racing technology.
Unlike the KTRC
system used on the GTR1400 ABS (Concours 14 ABS in N. America), which is
designed to offer rider
reassurance when traversing slippery surfaces, S-KTRC, is designed to maximize
forward motion,
allowing ...
Evaporative Emission Control System Inspection (CAL and SEA-B1 Models)
Inspect the canister as follows.
Remove the upper fairing assembly (see Upper Fairing
Assembly Removal in the Frame chapter).
Remove the canister [A].
Visually inspect the canister for cracks or other damage.
If the canister has any cracks or bad damage, replace it
with a new one.
NO ...
Air Cleaner
A clogged air cleaner restricts the engine’s
air intake, increasing fuel consumption,
reducing engine power, and
causing spark plug fouling.
This motorcycle’s air cleaner element
consists of a wet paper filter, which cannot
be cleaned.
The air cleaner element must be replaced
in acco ...