Ubs Diagram - Yamaha R1 Series 2015 Service Manual

Table of Contents

UBS diagram

1. Rear brake master cylinder

2. Front brake master cylinder

3. Hydraulic unit assembly (ABS ECU)

4. Front brake caliper (right)

5. Front brake caliper (left)

6. Rear brake caliper

When the brake lever is squeezed, the front brake master cylinder pressure sensor in the hydraulic

unit detects the hydraulic pressure. The ABS ECU calculates the appropriate rear brake force accord-

ing to the detected hydraulic pressure and sends a signal to the rear brake hydraulic pump. The hy-

draulic pump pressurizes the rear brake caliper using electronic control to operate the rear brake.

• If the brake pedal is depressed while the brake lever is being squeezed, the brake pedal may feel hard

due to the operation of the UBS, but this does not indicate a malfunction.

• If the rider squeezes the brake lever while resting their foot on the brake pedal, a vibration can be felt

at the brake pedal due to the operation of the UBS, but this does not indicate a malfunction.

• The UBS does not operate before the vehicle starts off.

• If the vehicle is stopped by operating the brake lever only, the brake force due to the operation

of the UBS will be maintained while the brake lever is squeezed. However, if the brake lever is

released, then squeezed again, the UBS will not operate.

• The unified brake system is a system to assist the brake operation. However, both the brake

lever and the brake pedal must be operated for maximum braking effect.

• Because the balance between the front brake calipers and the rear brake caliper in the unified

brake system is determined electronically, be sure to use the specified brake pads.

• Each set of brake pads should be checked individually and replaced if necessary.

b. Pressurization

c. Pressurization (hydraulic pump pressuriza-

tion by UBS)