Yamaha YZF-R125 Service Manual: 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"
- Valve "3"
- Valve spring "4"
- Upper spring seat "5" (into the cylinder head)
NOTE:
- Make sure each valve is installed in its original place.
- Install the valve springs with the larger pitch "a" facing up.
b. Smaller pitch
4. Install:
- Valve cotters "1"
NOTE:
Install the valve cotters by compressing the
valve spring with the valve spring compressor
and the valve spring compressor attachment "2".
5. To secure the valve cotters onto the valve stem, lightly tap the valve tip with a soft-face hammer.
| CAUTION: Hitting the valve tip with excessive force could damage the valve. |
Checking the valve springs
The following procedure applies to all of the
valve springs.
1. Measure:
Valve spring free length "a"
Out of specification Replace the valve
spring.
2. Measure:
Compressed valve ...
Other materials:
Checking the spark plug cap
1. Check:
Spark plug cap resistance
Out of specification Replace.
a. Remove the spark plug cap from the spark
plug lead.
b. Connect the pocket tester ( × 1k)
to the
spark plug cap as shown.
c. Measure the spark plug cap resistance. ...
Front wheel
To remove the front wheel
WARNING
To avoid injury, securely support the
vehicle so there is no danger of it
falling over.
Loosen the front wheel axle pinch
bolt, then the wheel axle and the
brake caliper bolts.
Front wheel axle pinch bolt
Lift the front wheel of ...
Fi system
The fuel pump delivers fuel to the fuel injector via the fuel filter. The
pressure regulator maintains the
fuel pressure that is applied to the fuel injector at only 250 kPa (2.50 kg/cm²,
36.3 psi). Accordingly,
when the energizing signal from the ECU energizes the fuel injector, the fuel ...