TOHATSU BFT 250A, Service Manual

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CYLINDER HEAD
CAMSHAFT RUNOUT
Measure the camshaft runout.
Camshaft runout is half of maximum gauge reading.
CYLINDER HEAD WARPAGE
Remove carbon deposits from the combustion
chamber.
Clean off any gasket material from the cylinder head
surface.
Check the spark plug holes and valve areas for cracks.
Check the cylinder head for warpage using a straight
edge [1] and a feeler gauge [2].
If the measurement exceeds the service limit,
recondition the cylinder head surface.
Reconditioning must be made within the standard value
of the cylinder head height.
Cylinder head reconditioning procedure:
Apply Prussian blue compound to the level block to
identify the warpage. Using a fine oil stone, grind the
cylinder head in a figure "8" pattern with the warped part
being the center of the ground part. Or use a lapping
machine to recondition the cylinder head.
CYLINDER HEAD HEIGHT
Measure the cylinder head height [1].
STANDARD: 0.030 mm (0.0012 in) Max.
SERVICE LIMIT: 0.040 mm (0.0016 in)
SERVICE LIMIT: 0.05 mm (0.002 in)
MEASUREMENT POINTS
[2]
[1]
STANDARD:
120.95 – 121.05 mm (4.762 – 4.766 in)
[1]