Yamaha YZF-R125 Service Manual: Checking the front brake disc

1. Remove:

• Front wheel Refer to "FRONT WHEEL" on page 4-6.

2. Check:

• Brake disc Damage/galling Replace.

3. Measure:

• Brake disc deflection Out of specification Correct the
  brake disc deflection or replace the brake disc.

a. Place the vehicle on a suitable stand so that the front wheel is elevated.

b. Before measuring the front brake disc deflection, turn the handlebar to the left or right to ensure that the front wheel is stationary.

c. Remove the brake caliper.

d. Hold the dial gauge at a right angle against the brake disc surface.

e. Measure the deflection 1.5 mm (0.06 in) below the edge of the brake disc.

4. Measure:

• Brake disc thickness Measure the brake disc thickness at a few different locations.

  Out of specification Replace.

5. Adjust:

• Brake disc deflection

a. Remove the brake disc.

b. Rotate the brake disc by one bolt hole.

c. Install the brake disc.

NOTE:

Tighten the brake disc bolts in stages and in a crisscross pattern.

d. Measure the brake disc deflection.

e. If out of specification, repeat the adjustment steps until the brake disc deflection is within specification.

f. If the brake disc deflection cannot be brought within specification, replace the brake disc.

6. Install:

• Front wheel Refer to "FRONT WHEEL" on page 4-6.