TOHATSU BFT250A Service Manual page 451

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Select the correct bearing by referring to the cylinder
block I.D. code letter or number and the crankshaft
main journal code number.
Crankshaft main bearing selection table
Crankshaft
main journal
code number
1 or I
2 or II
3 or III
4 or IIII
5 or IIIII
6 or IIIIII
Main bearing identification table
Main bearing center thickness: 2.5 mm (0.10 in)
Number I.D. color
F
E
D
C
B
A
When using bearing halves of different colors, it does
not matter which color is used in the top or bottom.
Each rod falls into one of six tolerance ranges (from -
0.009 mm (-0.0004 in) to 0.015 mm (0.0006 in)), in
0.004 mm (0.0002 in).
Note that the bearings are selected so that the oil
clearance is in the range between 0.020 – 0.046 mm
(0.0008 – 0.0018 in.)
After installing the selected bearing(s), measure the oil
clearance (page 15-34).
Apply molybdenum disulfide oil to the crankshaft mating
surface. Do not apply to the cylinder block and
crankcase mating surfaces.
Align the bearing tab [1] with the grooves in the
crankcase and cylinder block, and assemble carefully
not to damage the sliding surface.
• Be sure to measure the main bearing oil clearance
after selecting the bearing by referring to the
selection table.
• If the two bearing I.D. colors are shown on the
selection table, use a bearing of the respective
colors.
Cylinder block I.D. code number or
letter
A or I B or II C or III
Bearing I.D. color
Pink/
Pink Yellow
Yellow
Pink/ Yellow/
Yellow
Yellow Green
Yellow/
Yellow Green
Green
Yellow/ Green/
Green
Green Brown
Green/
Green Brown
Brown
Green/ Brown/
Brown
Brown Black
Tolerance ranges
–0.009 – –0.005 mm
Red
(–0.0004 – –0.0002 in)
–0.005 – –0.001 mm
Pink
(–0.0002 – –0.0001 in)
–0.001 – +0.003 mm
Yellow
(–0.0001 – +0.0001 in)
+0.003 – +0.007 mm
Green
(+0.0001 – +0.0003 in)
+0.007 – +0.011 mm
Brown
(+0.0003 – +0.0004 in)
+0.011 – +0.015 mm
Black
(+0.0004 – +0.0006 in)
D or IIII
Yellow/
Green
Green
Green/
Brown
Brown
Brown/
Black
Black
[1]
CYLINDER BLOCK
IDENTIFICATION COLOR
15-37