Ubs (Abs Not Activated And Ubs Activated) - Yamaha R1 Series 2015 Service Manual

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1. Front brake master cylinder
2. Brake lever
3. Rear brake master cylinder
4. Brake pedal
5. Separation solenoid valve
6. Shuttle solenoid valve
7. ABS motor
8. Hydraulic pump
9. Inlet solenoid valve
10.Outlet solenoid valve
11.Check valve

UBS (ABS not activated and UBS activated)

Brake lever input only
Front brakes:
When the ABS is not activated, the inlet solenoid valve is open and the outlet solenoid valve is closed
because a control signal has not been transmitted from the ABS ECU. Therefore, when the brake lever
is squeezed, the hydraulic pressure in the front brake master cylinder increases and the brake fluid is
sent to the front brake calipers. At this time, the hydraulic pump check valve is closed. The front brake
master cylinder directly pressurizes the front brake calipers during normal braking. When the brake le-
ver is released, the brake fluid in the front brake calipers returns to the front brake master cylinder.
Rear brake:
When the brake lever is squeezed, the ABS ECU detects the hydraulic pressure using the front brake
master cylinder pressure sensor and operates the hydraulic pump. At this time, the ABS is not activat-
ed, the inlet solenoid valve is open, and the outlet solenoid valve is closed because a control signal has
not been transmitted from the ABS ECU. The shuttle solenoid valve opens and closes according to the
UBS control signals from the ABS ECU. The hydraulic pump draws in the brake fluid from the rear brake
master cylinder and automatically pressurizes the rear brake caliper.
If the brake pedal is depressed, the UBS automatic pressurization stops. The ABS ECU detects and
controls the hydraulic pressure in the rear brake caliper using the front brake master cylinder pressure
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b
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12.Buffer chamber
13.Rear brake caliper
14.Front brake calipers
A. Pressurize
B. Depressurize
a. Input
b. Inlet solenoid valve is closed
c. Outlet solenoid valve is open
d. Hydraulic pump is operating
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FEATURES
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