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
RadiatorSpring Plate Free Play Measurement
Insufficient clutch free play will cause the engine braking
effect to be more sudden, resulting in rear wheel hop. On
the other hand, if the free play is excessive, the clutch lever
may feel “spongy” or pulsate when pulled.
Hold an extra drive shaft in a vise and install the following
c ...
Starter Motor Installation
NOTICE
Do not tap the starter motor shaft or body. Tapping
the shaft or body could damage the motor.
Clean the starter motor legs [A] and crankcase where the
starter motor is ground.
Replace the O-ring [A] with a new one.
Apply grease to the new O-ring.
Tighten:
Torque - Starter ...
Engine Oil Change
Situate the motorcycle so that it is vertical after warming
up the engine.
Remove the engine oil drain bolt [A] to drain the oil.
The oil in the oil filter can be drained by removing the filter
(see Oil Filter Replacement).
Replace the drain bolt gasket [B] with a new one.
Tighten t ...