TOHATSU BFT75A Service Manual page 419

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CYLINDER BLOCK
CRANKSHAFT/PISTON/CYLINDER
BLOCK INSPECTION
PISTON SKIRT O.D.
Check the piston outer surface for damage (scores,
scratches, etc.).
Check the piston for warpage and cracks.
Measure and record the piston O.D. [1] at 13 mm (0.5
in) [2] from the bottom and perpendicular to the piston
pin bore.
STANDARD:
72.98 – 72.99 mm (2.873 – 2.874 in)
SERVICE LIMIT:
72.97 mm (2.873 in)
If the measurement is less than the service limit,
replace the piston with a new one.
CYLINDER SLEEVE I.D.
Check the inner wall of the cylinder for damage (scores,
scratches, etc.).
Measure and record the cylinder I.D. at three levels in
both X and Y axes.
Take the maximum reading to determine the cylinder
I.D.
STANDARD:
73.00 – 73.02 mm (2.874 – 2.875 in)
SERVICE LIMIT:
73.07 mm (2.877 in)
If the measurement exceeds the service limit, replace
the cylinder block with a new one.
DIFFERENCE BETWEEN TOP AND
BOTTOM POINTS OF SLEEVE I.D.
Determine the difference of the cylinder sleeve I.D.
between the top and the bottom measurements.
SERVICE LIMIT:
0.05 mm (0.002 in)
If the measurement exceeds the service limit, replace
the cylinder block with a new one.
PISTON-TO-CYLINDER CLEARANCE
Determine the difference between the piston skirt O.D.
and the cylinder sleeve I.D.
STANDARD:
0.01 – 0.04 mm (0.0004 – 0.0016 in)
SERVICE LIMIT:
0.05 mm (0.002 in)
If the measurement exceeds the service limit, replace
the cylinder block with a new one.
15-18
[1]
[2]
90°
TOP
MIDDLE
X
Y
BOTTOM