If any one of the parts is damaged, replace the mechanical seal as a unit.
Rubber Seal [A] Mechanical Seal [B]

Water Pump Housing Assembly
RadiatorOil Pressure Measurement
Remove:
Right Lower Fairing (see Lower Fairing Removal in the
Frame chapter)
Oil Passage Plug [A]
Attach the adapter [A] and gauge [B] to the plug hole.
Special Tools - Oil Pressure Gauge, 10 kgf/cm²: 57001-164
Oil Pressure Gauge Adapter, PT3/8: 57001
-1233
...
Crankcase Splitting
Remove the engine (see Engine Removal in the Engine
Removal/Installation chapter).
Set the engine on a clean surface and hold the engine
steady while parts are being removed.
Remove:
Cylinder Head (see Cylinder Head Removal in the Engine
Top End chapter)
Starter Motor (see Starter M ...
Air Switching Valve (Service Code 64)
Air Switching Valve Removal/Installation
Refer to the Air Switching Valve Removal/Installation in
the Engine Top End chapter.
Air Switching Valve Inspection
Refer to the Air Switching Valve Unit Test in the Electrical
System chapter.
If the air switching valve [A] is normal, check ...