Kubota B1830, Workshop Manual, Page: 163 / 548

ENGINE B1830,B2230,B2530,B3030, WSM
1-S62
Oil Clearance between Crankpin and Crankpin Bearing
1. Clean the crankpin and crankpin bearing.
2. Put a strip of plastigage on the center of the crankpin.
3. Install the connecting rod cap and tighten the connecting rod
screws to the specified torque, and remove the cap again.
4. Measure the amount of the flattening with the scale, and get the
oil clearance.
5. If the oil clearance exceeds the allowable limit, replace the
crankpin bearing.
6. If the same size bearing is useless because of the crankpin
wear, replace it with an undersize one referring to the table and
figure.
NOTE
• Never insert the plastigage into the crankpin oil hole.
• Be sure not to move the crankshaft while the connecting
rod screws are tightened.
(Reference)
• Undersize dimensions of crankpin
9Y1210003ENS0104US0
Oil clearance between
crankpin and crankpin
bearing
Factory specification
0.029 to 0.091 mm
0.0011 to 0.0036 in.
Allowable limit
0.20 mm
0.0079 in.
Crankpin O.D. Factory specification
39.959 to 39.975 mm
1.5732 to 1.5738 in.
Crankpin bearing I.D. Factory specification
40.004 to 40.050 mm
1.5750 to 1.5768 in.
Undersize
0.2 mm
0.008 in.
0.4 mm
0.016 in.
Dimension A
2.8 to 3.2 mm radius
0.1102 to 0.1260 in. radius
2.8 to 3.2 mm radius
0.1102 to 0.1260 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
39.759 to 39.775 mm dia.
1.5653 to 1.5659 in. dia.
39.559 to 39.575 mm dia.
1.5574 to 1.5581 in. dia.
The crankpin 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