Yamaha YZF-R125 Service Manual: Checking the decompression system
1. Check:
- Decompression system
a. Check the decompression system with the camshaft sprocket and the decompression cam installed to the camshaft.
b. Check that the decompression lever "1" moves smoothly.
c. Without operating the decompression lever, check that the decompression cam "2" projects from the camshaft (exhaust cam) as shown in the illustration "A".
d. Move the decompression lever "1" in the direction of the arrow shown and check that the decompression cam does not project from the camshaft (exhaust cam) as shown in the illustration "B".
Checking the timing chain tensioner
1. Check:
Timing chain tensioner
Cracks/damage/rough movement Replace.
a. Lightly press the timing chain tensioner rod
into the timing chain tensioner housing by
hand.
NOTE:
While pressing the ...
Installing the cylinder head
1. Install:
Cylinder head
NOTE:
Pass the timing chain through the timing chain
cavity.
2. Tighten:
Cylinder head bolts "1"
Cylinder head bolts "2"
NOTE:
Lubricate the cylinder ...
Other materials:
Coolant
The coolant level should be checked
before each ride. In addition, the coolant
must be changed at the intervals
specified in the periodic maintenance
and lubrication chart.
To check the coolant level
Place the vehicle on a level surface
and hold it in an upright position.
TIP
...
Checking the camshaft
1. Check:
Camshaft lobes
Blue discoloration/pitting/scratches
Replace
the camshaft.
2. Measure:
Camshaft lobe dimensions "a" and "b"
Out of specification Replace
the camshaft.
3. Check:
Camshaft oil passage
Obstruction Blow out with
compressed air. ...
Installing the thermostat
1. Install:
Thermostat
NOTE:
Install the thermostat with its breather hole "a"
facing up.
2. Install:
Copper washer
Coolant temperature sensor
CAUTION:Use extreme care when handling the
coolant
temperature sensor. Replace any part that
was dropped or subjected to ...