Replace it if necessary.

Inner Tube Inspection
Spring Tension InspectionRear Master Cylinder Removal
Unscrew the brake hose banjo bolt [A] and remove the
brake hose (see Brake Hose and Pipe Replacement in
the Periodic Maintenance chapter).
Remove:
Rear Master Cylinder Mounting Bolts [B]
Foot Guard [C]
Screw and Stopper [D]
Bolt [E]
Front Footpeg Bracket Bolts [F]
Cable Guide [G ...
Valve Clearance
Valve and valve seat wear decreases
valve clearance, upsetting valve timing.
NOTICE
If valve clearance is left unadjusted,
wear will eventually
cause the valves to remain
partly open; which lowers performance,
burns the valves and
valve seats, and may cause serious
engine damage.
Valve cle ...
Special Tools and Sealant
Oil Pressure Gauge, 10 kgf/cm²:
57001-164
Oil Pressure Gauge Adapter, PT3/8:
57001-1233
Outside Circlip Pliers:
57001-144
Liquid Gasket, TB1211:
56019-120
...