If they appear damaged or deteriorated, replace them.

Balancer Adjustment
Torque LimiterThermostat Installation
Replace the O-rings [A] with new ones, and apply grease
to them.
Assemble:
O-rings
Thermostat Housing [B]
Thermostat [C]
Thermostat Cap [D]
Install the thermostat [A] in the housing so that the air
bleeder hole [B] is on top.
Tighten:
Torque - Thermostat Cap Bolts: 5.9 N ...
Steering Play Inspection
Remove the lower fairings (see Lower Fairing Removal in
the Frame chapter).
Raise the front wheel off the ground with the jack.
Special Tools - Jack: 57001-1238
Jack Attachment: 57001-1608
With the front wheel pointing straight ahead, alternately
tap each end of the handlebar. The f ...
Rear Shock Absorber Inspection
Press down on the seat several times
to inspect the stroke.
Visually inspect the rear shock absorber
for oil leaks.
If there is any doubt about the rear
shock absorber, it should be inspected
by an authorized Kawasaki
dealer.
A. Rear Shock Absorber
Spring Preload Adjustment
...