Honda BF40D Manual page 122

• CYLINDER HEAD WARPAGE
1) Remove the carbon deposits from the combustion
chamber. Clean off any gasket material from the cylinder
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head surface.
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2) Check the spark plug holes and valve seats for cracks.
3) Check the cylinder head for warpage using a straight edge
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and a feeler gauge.
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Standard
Less than 0.05 mm
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(0.002 in)
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4) If the measurement exceeds the service limit, recondition
the cylinder head.
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Cylinder head reconditioning procedure:
Apply Prussian Blue compound to the level block to identify
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the warpage, and using a fine oil stone, grind the cylinder
head in a "figure 8", with the warped part being the center
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of the ground part. Or use the lapping machine to
recondition the cylinder head.
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9-18
[1]
MEASUREMENT POINT:
Service limit
0.10 mm
(0.004 in)
122