Replace the gasket if it is damaged.
If they are clogged, remove the tank and drain it, and then blow the breather free with compressed air.

NOTICE
Do not apply compressed air to the air vent holes [D] in the tank cap. This could cause damage and clogging of the labyrinth in the cap.
Fuel Tank Installation
Fuel Tank CleaningBrake Light Switches
When either the front or rear brake is
applied, the brake light goes on. The
front brake light switch requires no adjustment,
but the rear brake light switch
should be adjusted in accordance with
the Periodic Maintenance Chart.
Inspection
Turn the ignition key to “ON”.
The brake ligh ...
Radiator and Cooling Fan
Check the radiator fins for obstruction
by insects or mud. Clean off
any obstructions with a stream of
low-pressure water.
WARNINGThe cooling fan spins at high
speed and can cause serious
injuries. Keep your hands and
clothing away from the cooling
fan blades at all times.
...
Front Caliper Removal
Remove:
Bolt [A]
Front Wheel Rotation Sensor [B]
Loosen the banjo bolt [C] at the brake hose lower end,
and tighten it loosely.
Unscrew the caliper mounting bolts [D], and detach the
caliper [E] from the disc.
NOTICE
Do not loosen the caliper assembly bolts [F]. Take
out only ...