Yamaha YZF-R125 Service Manual: 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 → Correct the brake disc deflection or replace the brake disc.
Refer to "CHECKING THE FRONT BRAKE
DISC" on page 4-21. 
4. Measure:
Brake disc thickness Measure the brake disc thickness at a few different locations.
Out of specification → Replace.
Refer to "CHECKING THE FRONT BRAKE
DISC" on page 4-21. 
5. Adjust:
- Brake disc deflection
Refer to "CHECKING THE FRONT BRAKE
DISC" on page 4-21.
6. Install:
- Rear wheel Refer to "REAR WHEEL" on page 4-12.
Introduction
WARNINGDisc brake components rarely require
disassembly.
Therefore, always follow these preventive
measures:
Never disassemble brake components unless
absolutely necessa ...
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 b ...
Other materials:
Adjusting the brake pedal free play
Adjusting the brake pedal free play
Brake pedal free play
The brake pedal free play should measure
3.5-4.5 mm (0.14-0.18 in) as
shown. Periodically check the brake
pedal free play and, if necessary, have
a Yamaha dealer adjust it.
WARNING
An incorrect brake pedal free play
in ...
Checking the spark plug
1. Remove:
Right side cover
Refer to "GENERAL CHASSIS" on page 4-1.
2. Disconnect:
Spark plug cap
3. Remove:
Spark plug
CAUTION:Before removing the spark plug, blow away
any dirt accumulated in the spark plug well
with compressed air to prevent it from falling
...
Troubleshooting details
This section describes the measures per fault code number displayed on the FI
diagnostic tool. Check
and service the items or components that are the probable cause of the
malfunction following the order
given.
After the check and service of the malfunctioning part have been completed,
re ...