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:
Checking the shift forks
The following procedure applies to all of the shift
forks.
1. Check:
Shift fork cam follower "1"
Shift fork pawl "2"
Bends/damage/scoring/wear
Replace the
shift fork.
2. Check:
Shift fork guide bar
Roll the shift fork guide bar on a flat surface.
Bends Replace. ...
Replacing a turn signal light bulb
Remove the turn signal light lens
by removing the screw.
Screw
Remove the burnt-out bulb by
pushing it in and turning it counterclockwise.
Insert a new bulb into the socket,
push it in, and then turn it clockwise
until it stops.
Install the lens by installing ...
Checking the ignition timing
NOTE:
Prior to checking the ignition timing, check the
wiring connections of the entire ignition system.
Make sure all connections are tight and free of
corrosion.
1. Remove:
Rider seat
Left lower side cowling
Refer to "GENERAL CHASSIS" on page 4-1.
2. Remove:
Timing mark acces ...