Kubota B1830, Workshop Manual, Page: 165 / 548

ENGINE B1830,B2230,B2530,B3030, WSM
1-S64
Oil Clearance between Crankshaft Journal and Crankshaft
Bearing 2 (Crankshaft Bearing 3)
1. Put a strip of plastigage on the center of the journal.
2. Install the bearing case and tighten the baring case screws 1 to
the specified torque, and remove the bearing case again.
3. Measure the amount of the flattening with the scale and get the
oil clearance.
4. If the clearance exceeds the allowable limit, replace the
crankshaft bearing 2 (1) and crankshaft bearing (3).
5. 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.
NOTE
• Be sure not to move the crankshaft while the bearing case
screws are tightened.
(Reference)
• Undersize dimensions of crankshaft journal
9Y1210003ENS0107US0
Oil clearance between
crankshaft journal and
crankshaft bearing 2
Factory specification
0.034 to 0.095 mm
0.0013 to 0.0037 in.
Allowable limit
0.20 mm
0.0079 in.
Crankshaft journal O.D.
(Intermediate)
Factory specification
47.934 to 47.950 mm
1.8872 to 1.8878 in.
Crankshaft bearing 2
I.D.
Factory specification
47.984 to 48.029 mm
1.8891 to 1.8909 in.
Oil clearance between
crankshaft journal and
crankshaft bearing 3
Factory specification
0.034 to 0.098 mm
0.0013 to 0.0039 in.
Allowable limit
0.20 mm
0.0079 in.
Crankshaft journal O.D.
(Flywheel side)
Factory specification
51.921 to 51.940 mm
2.0441 to 2.0449 in.
Crankshaft bearing 3
I.D.
Factory specification
51.974 to 52.019 mm
2.0462 to 2.0480 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.
Dimension D
51.721 to 51.740 mm dia.
2.0362 to 2.0370 in. dia.
51.521 to 51.540 mm dia.
2.0284 to 2.0291 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.
KiSC issued 05, 2012 A