Replace it if necessary.

Inner Tube Inspection
Spring Tension InspectionWater Pump Impeller Disassembly/Assembly
Remove the water pump impeller (see Oil Pump Removal
in the Engine Lubrication System chapter).
The sealing seat and rubber seal may be removed easily
by hand.
Apply coolant around the surfaces of the rubber seal and
sealing seat.
Install the rubber seal [A] and sealing seat [B] into ...
Valve-to-Guide Clearance Measurement (Wobble Method)
If a small bore gauge is not available, inspect the valve
guide wear by measuring the valve to valve guide clearance
with the wobble method as indicated below.
Insert a new valve [A] into the guide [B] and set a dial
gauge against the stem perpendicular to it as close as
possible to the cy ...
Swingarm Bearing Installation
Replace the needle bearings, ball bearing, grease seals
and circlip with new ones.
Install the needle bearings, ball bearing, grease seals and
circlip as shown in the figure.
Insert the needle bearing driver [A] into the needle bearing
[B] and press the needle bearing into the housing u ...