Yamaha 2003 FJR1300, Service Manual

Page: 74 / 162

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CHAS
• Hydraulic control valve
The hydraulic control valve is composed of a
flow control valve and solenoid valve.
When the ABS is activated, the flow control
valve regulates the flow of brake fluid to each
brake and the solenoid valve decreases and
increases the brake fluid pressure.
1) When the brakes are operated normally, the
solenoid valve
2
is closed, the spool
3
of
the flow control valve does not move, and
the hydraulic line between the brake master
cylinder and brake caliper is open.
2) When the ABS is activated, the solenoid
valve
2
is opened by the power supplied
from the ECU (ABS) signals to decrease
the brake fluid pressure and the spool
3
of
the flow control valve is moved toward the
solenoid valve.
3) When the ECU (ABS) stops transmitting
signals to decrease the brake fluid pres-
sure, the solenoid valve
2
closes and the
brake fluid is pressurized again. Pressuriz-
ing the brake fluid again, while the ABS is
activated, limits the flow of the brake fluid
with the movement of the flow control valve
spool
3
and provides a gradual pressure
increase.
1
Orifice
2
Solenoid valve
3
Spool
4
Flow control valve
ANTI-LOCK BRAKE SYSTEM (FJR1300A)