2-15
PERIODIC MAINTENANCE
AIR BLEEDING OF THE BRAKE FLUID
CIRCUIT
Air trapped in the brake fluid circuit acts like a cushion to
absorb a large proportion of the pressure developed by
the master cylinder and thus interferes with the full brak-
ing performance of the brake caliper. The presence of
air is indicated by sponginess of the brake lever and
also by lack of braking force. Considering the danger to
which such trapped air exposes the machine and rider,
it is essential that, after remounting the brake and
restoring the brake system to the normal condition, the
brake fluid circuit be purged of air in the following man-
ner :
Fill the master cylider reservoir to top of the inspec-
tion window. Replace the reservoir cap to prevent dirt
from entering it.
Attach a hose to the air bleeder valve, and insert the
free end of the hose into a receptacle.
Bleed air from the brake system.
Squeeze and release the brake lever several times in
rapid succession and sqeeze the lever fully without
releasing it. Loosen the bleeder valve by turning it a
quarter of a turn so that the brake fluid runs into the
receptacle, this will remove the tension of the brake
lever causing it to touch the handlebar grip. Then,
close the air bleeder valve, pump and squeeze the
brake lever, and open the valve. Repeat this process
until the fluid flowing into the receptacle no longer
contains air bubbles.
Close the air bleeder valve, and disconnect the hose.
Fill the reservoir with brake fluid to the upper line.
Front brake caliper air bleeder valve
: 6~9 N
m (0.6~0.9 kg
m)
NOTE
While bleeding the brake system, replenish the
brake fluid in the reservoir as necessary. Make
sure that there is always some fluid visible in the
reservoir.
CAUTION
Handle brake fluid with care : the fluid reacts
chemically with paint, plastics, rubber materials,
etc.
