Yamaha YZF-R125 Service Manual: Replacing the rear brake pads
NOTE:
When replacing the brake pads, it is not necessary to disconnect the brake hose or disassemble the brake caliper.
1. Remove:
- Brake pads
- Brake pad spring
NOTE:
To remove the inner brake pad "1", push down on the brake caliper bracket so that there is space to remove the brake pad.
2. Measure:
Brake pad wear limit "a"
Out of specification → Replace the brake
pads as a set. 
3. Install:
- Brake pad spring
- Brake pads
NOTE:
Always install new brake pads and a new brake pad spring as a set.
a. Connect a clear plastic hose tightly to the bleed screw. Put the other end of the hose into an open container.
b. Loosen the bleed screw and push the brake caliper piston into the brake caliper with your finger.
c. Tighten the bleed screw. 
d. Install a new brake pad spring "1" and new brake pads.
NOTE:
Install the brake pad spring as shown.
4. Install:
- Brake pad retaining bolts
- Brake caliper
5. Install:
- Rear wheel Refer to "REAR WHEEL" on page 4-12.
6. 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.
7. Check:
- Brake pedal operation
Soft or spongy feeling Bleed
the brake system.Refer to "BLEEDING THE HYDRAULIC BRAKE SYSTEM" on page 3-20.
Checking the rear brake disc
1. Remove:
Rear wheel
Refer to "REAR WHEEL" on page 4-12.
2. Check:
Brake disc
Damage/galling → Replace.
3. Measure:
Brake disc deflection
Out of specification → Correc ...
Removing the rear brake caliper
NOTE:
Before disassembling the brake caliper, drain
the brake fluid from the entire brake system.
1. Remove:
Union bolt "1"
Copper washers "2"
Brake hose "3"
NOTE:
Put the end of th ...
Other materials:
Checking the front and rear brake pads
The front and rear brake pads must be
checked for wear at the intervals specified
in the periodic maintenance and
lubrication chart.
Front brake pads
Remove the front brake caliper by
removing the bolts.
Bolt
Brake caliper
Lining thickness
Check each front br ...
Checking the primary drive gear
1. Remove:
Primary drive gear
Refer to "BALANCER GEAR" on page 5-53.
2. Check:
Primary drive gear
Damage/wear Replace the
primary drive
gear and clutch housing as a set.
Excessive noise during operation
Replace
the primary drive gear and clutch housing as
a set
...
Catalytic converters
This vehicle is equipped with catalytic
converters in the exhaust system.
WARNING
The exhaust system is hot after operation.
To prevent a fire hazard or
burns:
Do not park the vehicle near
possible fire hazards such as
grass or other materials that
easily burn.
Park the vehic ...