Kubota B1830, Workshop Manual

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ENGINE B1830,B2230,B2530,B3030, WSM
1-S63
Oil Clearance between Crankshaft Journal and Crankshaft
Bearing 1
1. Measure the O.D. of the crankshaft front journal with an outside
micrometer.
2. Measure the I.D. of the crankshaft bearing 1 with an inside
micrometer, and calculate the oil clearance.
3. If the clearance exceeds the allowable limit, replace the
crankshaft bearing 1.
4. If the same size bearing is useless because of the crankshaft
journal wear, replace it with an undersize one referring to the
table and figure.
(Reference)
• Undersize dimensions of crankshaft journal
9Y1210003ENS0105US0
Replacing Crankshaft Bearing 1
(When removing)
1. Press out the used crankshaft bearing 1 using a crankshaft
bearing 1 replacing tool. (See page "SPECIAL TOOLS".)
(When installing)
1. Clean a new crankshaft bearing 1 and crankshaft journal bore,
and apply engine oil to them.
2. Using a crankshaft bearing 1 replacing tool, press in a new
bearing 1 (2) so that its seam (1) directs toward the exhaust
manifold side. (See figure.)
9Y1210003ENS0106US0
Oil clearance between
crankshaft journal and
crankshaft bearing 1
Factory specification
0.034 to 0.114 mm
0.0013 to 0.0045 in.
Allowable limit
0.20 mm
0.0079 in.
Crankshaft journal O.D. Factory specification
47.934 to 47.950 mm
1.8872 to 1.8878 in.
Crankshaft bearing 1
I.D.
Factory specification
47.984 to 48.048 mm
1.8891 to 1.8916 in.
Undersize
0.2 mm
0.008 in.
0.4 mm
0.016 in.
Dimension A
2.3 to 2.7 mm radius
0.0906 to 0.1063 in. radius
2.3 to 2.7 mm radius
0.0906 to 0.1063 in. radius
*Dimension B
1.0 to 1.5 mm relief
0.0394 to 0.0591 in. relief
1.0 to 1.5 mm relief
0.0394 to 0.0591 in. relief
Dimension C
47.734 to 47.750 mm dia.
1.8793 to 1.8799 in. dia.
47.534 to 47.550 mm dia.
1.8714 to 1.8720 in. dia.
The crankshaft journal must be fine-finished to higher than Rmax = 0.8-S.
*Holes to be de-burred and edges rounded with 1.0 to 1.5 mm
(0.0394 to 0.0591 in.) relief.
Dimension (A) Factory specification
0 to 0.3 mm
0 to 0.0118 in.
(1) Seam
(2) Crankshaft Bearing 1 (3) Cylinder Block
(A) Dimension
KiSC issued 05, 2012 A