seats YAMAHA TTR125 2004 Betriebsanleitungen (in German)

4 - 15
ENGCYLINDER HEAD
4. Remove:
Bolt (camshaft sprocket) 1
Camshaft sprocket 2
NOTE:
Attach a wire a to the timing chain to prevent
it from falling into the crankcase.
5. Remove:
Bolts (cylinder head)
Cylinder head
NOTE:
Loosen the bolts 1/4 turn each and remove
then after all are loosened.
Loosen the bolts starting with the lowest
number one.
INSPECTION
Cylinder head
1. Eliminate:
Carbon deposits (from the combustion
chambers)
Use a rounded scraper.
NOTE:
Do not use a sharp instrument to avoid dam-
aging or scratching:
Spark plug threads
Valve seats
2. Inspect:
Cylinder head
Scratches/damage → Replace.
3. Inspect:
Cylinder head warpage
Out of specification → Re-surface.
Warpage measurement and re-surfacing
steps:
Attach a straightedge and a thickness
gauge on the cylinder head.
Measure the warpage.

4 - 27
ENGVALVES AND VALVE SPRINGS
3. Inspect:
Valve face
Pitting/wear → Grind the face.
Valve stem end
Mushroom shape or diameter larger
than the body of the stem → Replace.
4. Measure:
Margin thickness a
Out of specification → Replace.
5. Measure:
Runout (valve stem)
Out of specification → Replace.
NOTE:
When installing a new valve always replace
the guide.
If the valve is removed or replaced always
replace the oil seal.
Margin thickness:
Intake:
0.4 ~ 0.8 mm
(0.0157 ~ 0.0315 in)
Exhaust:
0.8 ~ 1.2 mm
(0.0315 ~ 0.0472 in)
Runout limit:
0.01 mm (0.0004 in)
6. Eliminate:
Carbon deposits
(from the valve face and valve seat)
7. Inspect:
Valve seats
Pitting/wear → Reface the valve seat.

4 - 30
ENGVALVES AND VALVE SPRINGS
2. Measure:
Compressed spring force a
Out of specification → Replace.
bInstalled length
3. Measure:
Spring tilt a
Out of specification → Replace.
Compressed spring force:
Intake:
14.0 ~ 16.1 kg at 25.6 mm
(30.86 ~ 35.49 lb at 1.01 in)
Exhaust:
14.0 ~ 16.1 kg at 25.6 mm
(30.86 ~ 35.49 lb at 1.01 in)
Spring tilt limit:
Intake:
2.5˚/1.4 mm (0.06 in)
Exhaust:
2.5˚/1.4 mm (0.06 in)
ASSEMBLY AND INSTALLATION
Valve
1. Apply:
Molybdenum disulfide oil
(onto the valve stem and valve stem
seal)
2. Install:
Valve spring seats 1
Valve stem seals 2
Valves 3
Valve springs 4
Valve spring retainers 5
NOTE:
Make sure that each valve is installed in its
original place.
Install the valve springs with the larger pitch
a facing upwards.
bSmaller pitch
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