TOHATSU BFT75A Service Manual page 423

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CYLINDER BLOCK
CRANK PIN JOURNAL O.D.
Measure the crank pin journal [1] O.D.
STANDARD:
39.976 – 40.000 mm (1.5739 – 1.5748 in)
CRANKSHAFT JOURNAL (MAIN, PIN)
ROUNDNESS
Measure the crankshaft main journal O.D. and the
crank pin O.D. in the A and B directions.
Calculate the difference between the measurements to
determine the roundness.
STANDARD:
0.005 mm (0.0002 in) max.
SERVICE LIMIT:
0.010 mm (0.0004 in)
If the measurement exceeds the service limit, replace
the crankshaft with a new one.
CRANKSHAFT JOURNAL (MAIN, PIN)
CYLINDRICITY
Measure the crankshaft main journal O.D. and the
crank pin O.D. at the C and D locations.
Calculate the difference between the measurements to
determine the cylindricity.
STANDARD:
0.005 mm (0.0002 in) max.
SERVICE LIMIT:
0.010 mm (0.0004 in)
If the measurement exceeds the service limit, replace
the crankshaft with a new one.
CONNECTING ROD BOLT O.D.
Measure the O.D. of each connecting rod bolt at two
points as shown.
Calculate
measurements.
STANDARD:
0 – 0.05 mm (0 – 0.002 in)
SERVICE LIMIT:
0.05 mm (0.002 in)
If the measurement exceeds the service limit, replace
the connecting rod bolt with a new one.
• Measure the O.D. on each connecting rod bolt.
15-22
the difference between
Measure the roundness at the
center of the journal.
Measure the cylindricity at both ends
of the journal.
ROUNDNESS:
CYLINDRICITY:
the two
15 mm (0.6 in)
[1]
B
A
C D
30 mm (1.2 in)