Yamaha YZF-R125 Service Manual: Removing the valves
The following procedure applies to all of the valves and related components.
NOTE:
Before removing the internal parts of the cylinder head (e.g., valves, valve springs, valve seats), make sure the valves properly seal.
1. Check:
- Valve sealing
Leakage at the valve seat
Check
the valve face, valve seat, and valve seat width.Refer to "CHECKING THE VALVE SEATS" on page 5-20.
a. Pour a clean solvent "a" into the intake and exhaust ports.
b. Check that the valves properly seal.
NOTE:
There should be no leakage at the valve seat "1".
2. Remove:
- Valve cotters "1"
NOTE:
Remove the valve cotters by compressing the
valve spring with the valve spring compressor
and the valve spring compressor attachment "2".
3. Remove:
- Upper spring seat "1"
- Valve spring "2"
- Valve "3"
- Valve stem seal "4"
- Lower spring seat "5"
NOTE:
Identify the position of each part very carefully so that it can be reinstalled in its original place.
Checking the valves and valve guides
The following procedure applies to all of the
valves and valve guides.
1. Measure:
Valve-stem-to-valve-guide clearance
Out of specification Replace the
valve
guide.
Valve-stem-to-valve ...
Other materials:
Installing the starter clutch
1. Install:
Starter clutch assembly
Starter clutch bolts "1"
NOTE:
While holding the generator rotor "2" with the
sheave holder "3", tighten the starter clutch
bolts.
Do not allow the sheave holder to touch the
projection on the generator rotor.
Stake the end "a" of each start ...
Unstable handling
Handlebars
- Bent or improperly installed right handlebar
- Bent or improperly installed left handlebar
1. Steering head components
- Improperly installed upper bracket
- Improperly installed lower bracket
(improperly tightened ring nut)
- Bent steering stem
- Damaged ball bearing or bearing ...
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 the recommended lubricant)
3. Install:
Lower spring seat "1"
Valve stem seal "2"
V ...