Yamaha YZF-R125 Service Manual: Replacing the front brake pads
NOTE:
When replacing the brake pads, it is not necessary to disconnect the brake hose or disassemble the brake caliper.
1. Measure:
- Brake pad wear limit "a"
Out of specification
Replace
the brake pads as a set.
2. Install:
- Brake pad support
- Brake pad spring
- Brake pads
NOTE:
Always install new brake pads, a new brake pad spring and a new brake pad support as a set.
a. Connect a clear plastic hose "1" tightly to the bleed screw "2". Put the other end of the hose into an open container.
b. Loosen the bleed screw and push the brake caliper pistons into the brake caliper with your fingers.
c. Tighten the bleed screw. 
d. Install new brake pad support, a new brake pad spring and new brake pads.
NOTE:
The arrow mark "a" on the brake pad spring must point in the direction of disc rotation.
3. Install:
- Brake pad pin
- Brake pad clips
- Front brake caliper
4. Check:
- Brake fluid level
Below the minimum level mark "a" → Add
the
recommended brake fluid to the proper level.
Refer to "CHECKING THE BRAKE FLUID LEVEL" on page 3-18.
5. Check:
- Brake lever operation
Soft or spongy feeling
Bleed
the brake system.Refer to "BLEEDING THE HYDRAULIC BRAKE SYSTEM" on page 3-20.
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
b ...
Removing the front brake caliper
NOTE:
Before disassembling the brake caliper, drain
the brake fluid from the entire brake system.
1. Remove:
Brake hose union bolt "1"
Copper washers "2"
Brake hose "3"
NOTE:
Put the en ...
Other materials:
Checking the front brake master cylinder
1. Check:
Brake master cylinder
Damage/scratches/wear Replace.
Brake fluid delivery passages
(brake master cylinder body)
Obstruction Blow out with
compressed air.
2. Check:
Brake master cylinder reservoir
Cracks/damage Replace the brake
master
cylinder.
Brake maste ...
Throttle position sensor
1. Check:
Throttle position sensor
a. Connect the digital circuit tester to the terminals
of the throttle body sensor assembly
coupler as shown.
Positive tester probe →
gray/red terminal "1"
Negative tester probe →
gray/black terminal "2"
b. Measure the throttle pos ...
Removing the valves
The following procedure applies to all of the
valves and related components.
NOTE:
Before removing the internal parts of the cylinder
head (e.g., valves, valve springs, valve seats),
make sure the valves properly seal.
1. Check:
Valve sealing
Leakage at the valve seat Check
the valve
...