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Valve spring compressor 90890-04019, YM-04019
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Valve spring compressor attach-ment
YM-04114
5 - 21
VALVES AND VALVE SPRINGS ENG
Л Remove:
valve retainer 1
valve spring 2
valve stem seal 3
valve spring seat 4
valve 5
NOTE:
Identify the position of each part very carefully so that it can be reinstalled in its original place.
EAS00239
CHECKING THE VALVES AND VALVE
GUIDES
The following procedure applies to all of the valves and valve guides.
М Measure:
valve-stem-to-valve-guide clearance
Valve-stem-to-valve-guide clearance =
Valve guide inside diameter a –
Valve stem diameter b
Out of specification → Replace the valve guide.
Valve-stem-to-valve-guide clear-ance
Intake
0.010 ~ 0.037 mm
(0.0004 ~ 0.0015 in)
<Limit>: 0.080 mm (0.0031 in) Exhaust
0.025 ~ 0.052 mm
(0.0010 ~ 0.0020 in)
<Limit>: 0.100 mm (0.0039 in)
П Replace:
valve guide
NOTE:
To ease valve guide removal and installation, and to maintain the correct fit, heat the cylinder head to 100 °C (212 °F) in an oven.
5 - 22
VALVES AND VALVE SPRINGS ENG
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Р Remove the valve guide with a valve guide remover 1.
Р Install the new valve guide with a valve guide installer 2 and valve guide remover
1.
Р After installing the valve guide, bore the valve guide with a valve guide reamer 3 to obtain the proper valve-stem-to-valve-guide clearance.
NOTE:
After replacing the valve guide, reface the valve seat.
Valve guide remover (4 mm) 90890-04111, YM-04111 Valve guide installer (4 mm) 90890-04112, YM-04112 Valve guide reamer (4 mm) 90890-04113, YM-04113
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С Eliminate:
carbon deposits
(from the valve face and valve seat)
С Check:
valve face
Pitting/wear → Grind the valve face.
valve stem end
Mushroom shape or diameter larger than the body of the valve stem → Replace the valve.
С Measure:
valve margin thickness a
Out of specification → Replace the valve.
Valve margin thickness
0.6 ~ 0.8 mm (0.0236 ~ 0.0315 in) <Limit>: 0.5 mm (0.0197 in)
5 - 23
VALVES AND VALVE SPRINGS ENG
Т Measure:
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valve stem runout
Out of specification → Replace the valve.
NOTE:
У When installing a new valve, always replace the valve guide.
У If the valve is removed or replaced, always replace the oil seal.
Valve stem runout 0.04 mm (0.0016 in)
EAS00240
CHECKING THE VALVE SEATS
The following procedure applies to all of the valves and valve seats.
Х Eliminate:
carbon deposits
(from the valve face and valve seat)
Х Check:
valve seat
Pitting/wear → Replace the cylinder head.
Х Measure:
valve seat width a
Out of specification → Replace the cylinder head.
Valve seat width Intake
0.9 ~ 1.1 mm
(0.0354 ~ 0.0433 in) <Limit>: 1.6 mm (0.06 in)
Exhaust
0.9 ~ 1.1 mm
(0.0354 ~ 0.0433 in) <Limit>: 1.6 mm (0.06 in)
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П Apply Mechanic’s blueing dye (Dykem) b onto the valve face.
5 - 24
VALVES AND VALVE SPRINGS ENG
Р Install the valve into the cylinder head.
Р Press the valve through the valve guide and onto the valve seat to make a clear impres-sion.
Р Measure the valve seat width.
NOTE:
Where the valve seat and valve face contacted one another, the blueing will have been removed.
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С Lap:
valve face
valve seat
NOTE:
After replacing the cylinder head or replacing the valve and valve guide, the valve seat and valve face should be lapped.
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У Apply a coarse lapping compound a to the valve face.
CAUTION:
Do not let the lapping compound enter the gap between the valve stem and the valve guide.
Ф Apply molybdenum disulfide oil onto the valve stem.
Ф Install the valve into the cylinder head.
Ф Turn the valve until the valve face and valve seat are evenly polished, then clean off all of the lapping compound.
NOTE:
For the best lapping results, lightly tap the valve seat while rotating the valve back and forth between your hands.
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VALVES AND VALVE SPRINGS ENG
Ц Apply a fine lapping compound to the valve face and repeat the above steps.
Ц After every lapping procedure, be sure to clean off all of the lapping compound from the valve face and valve seat.
Ц Apply Mechanic’s blueing dye (Dykem) onto the valve face.
Ц Install the valve into the cylinder head.
Ц Press the valve through the valve guide and onto the valve seat to make a clear impres-sion.
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Ц Measure the valve seat width b again. If the valve seat width is out of specification,
reface and lap the valve seat.
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EAS00241
CHECKING THE VALVE SPRINGS
The following procedure applies to all of the valve springs.
• Measure:
valve spring free length a
Out of specification → Replace the valve spring.
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