Yamaha YP250A 1999 Supplementary Service Manual page 20

2) Pressurized state
Port D 12 of solenoid valve closes according to the "increase pressure" signal from the electronic control
unit. Also, spool 9 of flow control valve compresses the return spring to close the port B
Brake fluid entered through port A 8 is further restricted by the orifice
Accordingly, the brake fluid in master cylinder is sent in the line of Port A 8 , Port C
caliper. However, the brake is pressurized at a constant speed regardless of the brake fluid pressure
level since the port A's 8 restriction changes so that the constant pressure difference is maintained be-
tween A 21 and B 22 chambers of flow control valve.
ABS OUTLINE
Brake master
1
cylinder
Brake switch
2
Silencer chamber
3
Motor
4
Pump
5
Buffer chamber
6
Flow control valve
7
Port A
8
Spool
9
Port B
10
Orifice
11
12
GEN
INFO
.
10
11 .
then to the brake
14
Port D
12
Solenoid valve
13
Port C
14
Brake caliper
15
Electronic control
16
unit
ABS warning light
17
Brake fluid pressure
18
Time
19
Repressurizing
20
Chamber A
21
Chamber B
22