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:
Ignition circuit cut-off system
The ignition circuit cut-off system (comprising
the sidestand switch, clutch
switch and neutral switch) has the following
functions.
It prevents starting when the transmission
is in gear and the sidestand
is up, but the clutch lever is
not pulled.
It prevents starting when the t ...
Setting the diagnostic mode
1. Set the main switch to "OFF" and the engine stop switch to "
".
2. Disconnect the self-diagnosis signal connector "1", and then connect the FI
diagnostic tool "2" as
shown.
3. Disconnect the fuel pump coupler.
4. While pressing the "MODE" button, set the main switch to "ON".
NOTE:
...
Adjusting the front wheel static balance
NOTE:
After replacing the tire, wheel or both, the front
wheel static balance should be adjusted.
Adjust the front wheel static balance with the
brake discs installed.
1. Remove:
Balancing weight(s)
2. Find:
Front wheel's heavy spot
NOTE:
Place the front wheel on a suitab ...