Yamaha YZF-R125 Service Manual: Cylinder and piston
- Removing the piston
- Checking the cylinder and piston
- Checking the piston rings
- Checking the piston pin
- Installing the piston and cylinder
Installing the valves
The following procedure applies to all of the
valves and related components.
1. Deburr:
Valve stem end
(with an oil stone)
2. Lubricate:
Valve stem "1"
Valve stem seal "2"
(with ...
Removing the piston
1. Remove:
Piston pin clips "1"
Piston pin "2"
Piston "3"
CAUTION:Do not use a hammer to drive the piston
pin
out.
NOTE:
Before removing the piston pin c ...
Other materials:
Checking the front brake lever free play
Checking the front brake lever free play
Brake lever free play
The brake lever free play should measure
2.0-5.0 mm (0.08-0.20 in) as
shown. Periodically check the brake lever
free play and, if necessary, have a
Yamaha dealer check the brake system.
WARNING
An incorrect brake le ...
Checking the rectifier/regulator
1. Check:
Rectifier/regulator output voltage
Out of specification → Replace the
rectifier/
regulator.
a. Set the engine tachometer to the spark plug
lead.
b. Connect the pocket tester (DC 20 V) to the
rectifier/regulator coupler as shown.
Positive tester probe
red "1"
Negat ...
Checking the cylinder and piston
1. Check:
Piston wall
Cylinder wall
Vertical scratches Replace the
cylinder,
and replace the piston and piston rings as a
set.
2. Measure:
Piston-to-cylinder clearance
a. Measure cylinder bore "C" with the cylinder
bore gauge.
NOTE:
Measure cylinder bore "C" by takin ...