If they appear damaged or deteriorated, replace them.

Balancer Adjustment
Torque LimiterECU Removal
NOTICE
Never drop the ECU especially on a hard surface.
Such a shock to the ECU can damage it.
Remove the upper air cleaner housing (see Air Cleaner
Element Replacement in the Periodic Maintenance chapter).
Lift up the ECU [A] with rubber protector [B] to disconnect
the connectors [C]. ...
Fuel Tank and Cap Inspection
Visually inspect the gasket [A] on the tank cap for any
damage.
Replace the gasket if it is damaged.
Check to see if the water drain pipe [B] and fuel breather
pipe [C] in the tank are not clogged. Check the tank cap
breather also.
If they are clogged, remove the tank and drain it ...
Chain Slack Adjustment
Remove the cotter pin, and loosen
the axle nut.
Loosen the left and right chain adjuster
locknuts.
A. Axle Nut
B. Cotter Pin
C. Adjuster
D. Locknut
If the chain is too loose, turn out the
left and right chain adjusters evenly.
If the chain is too tight, turn in the left
...