17 .4.25 Checking the cylinder head
302808-10
17.4.26 valves, installing
17 ENGINE
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Check valve guides
O
using the special tool.
I
Limit plug gauge (77229026000) (
lll:!l
p. 291)
If the special tool is easy to insert in the valve guide:
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Change the valve guide and valve.
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Check the sealing area of the spark plug thread and the valve
seats from damage and cracking.
If there is damage or cracking:
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Change the cylinder head.
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Using a straightedge and the special tool, check the sealing
area of the cylinder for distortion.
I
Feeler gauge (590290411 00) (
lll:!l
p. 288)
Cylinder/cylinder head -
distortion of sealing area
s 0.10 mm (s 0.0039 in)
If the measured value does not meet specifications:
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Change the cylinder head.
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Check sealing seat
f)
of the valves.
Valve - sealing seat width
Intake
1 .40 mm (0.0551 in)
Valve - sealing seat width
Exhaust
1 .40 mm (0.0551 in)
If the measured value does not meet specifications:
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Rework the valve seat.
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Blow compressed air through all oil holes and check that they
are clear.
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Position valve spring seat
O.
Mount valve stem seal@.
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Mount the valve corresponding to its installation position.
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Mount the valve spring with the tighter coil facing downward
according to the built-in position.
Mount the valve spring retainers.
199