Yamaha YZF-R125 Service Manual: Installing the piston and cylinder
1. Install:
- Top ring "1"
- 2nd ring "2"
- Oil ring expander "3"
- Lower oil ring rail "4"
- Upper oil ring rail "5"
NOTE:
Be sure to install the piston rings so that the manufacturer marks or numbers face up.
2. Install:
- Piston "1"
- Piston pin "2"
- Piston pin clips "3"
NOTE:
- Apply engine oil to the piston pin.
- Make sure the arrow mark "a" on the piston points towards the exhaust side of the cylinder.
- Before installing the piston pin clips, cover the crankcase opening with a clean rag to prevent the clips from falling into the crankcase.
3. Lubricate:
- Piston
- Piston rings
- Cylinder
(with the recommended lubricant)
4. Offset:
- Piston ring end gaps
a. Top ring
b. Upper oil ring rail
c. Oil ring expander
d. Lower oil ring rail
e. 2nd ring
f. 20 mm (0.79 in)
A. Intake side
5. Install:
- Dowel pins
- Cylinder head gasket
- Cylinder "1"
NOTE:
- While compressing the piston rings with one hand, install the cylinder with the other hand.
- Pass the timing chain and timing chain guide (intake side) through the timing chain cavity.
Checking the piston pin
1. Check:
Piston pin
Blue discoloration/grooves
Replace the
piston pin and then check the lubrication system.
2. Measure:
Piston pin outside diameter "a"
Out of specification ...
Other materials:
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 ...
Rear wheel
To remove the rear wheel
WARNING
To avoid injury, securely support the
vehicle so there is no danger of it
falling over.
Loosen the axle nut.
Axle nut
Drive chain slack adjusting bolt
Locknut
Brake caliper
Lift the rear wheel off the ground
according to the pr ...
Checking the starter motor operation
1. Check:
Starter motor operation
Does not operate → Perform the electric
starting system troubleshooting, starting with
step 4.
Refer to "TROUBLESHOOTING" on page
8-9.
a. Connect the positive battery terminal "1" and
starter motor lead "2" with a jumper lead "3".
W ...