Undersize Main Bearing Selection

1. If new standard bearings do not produce the correct oil clearance, regrind the crankshaft to a finished diameter of 57.732-57.750 mm (2.2729-2.2736 inch) and install 0.25 mm (0.0098 inch) undersize bearings. Undersize bearings are available in 5 sizes (tolerances) differing in thickness in the center of the bearing.





2. Undersize bearings are distinguished from standard size bearings by a double paint mark (1).
^ Green and red paint indicates a bearing thickness of 2.121-2.125 mm (0.0835-0.0836 inch).
^ Black and red paint indicates a bearing thickness of 2.124-2.128 mm (0.0836-0.0837 inch).
^ Red paint only indicates a bearing thickness of 2.127-2.131 mm (0.0837-0.0838 inch).
^ Yellow and red paint indicates a bearing thickness of 2.130-2.134 mm (0.0838-0.0839 inch).
^ Blue and red paint indicates a bearing thickness of 2.133-2.137 mm (0.0839-0.0840 inch).





3. Measure the reground crankshaft journals for out-of-round.
Maximum Out-of-Round: 0.01 mm (0.0004 inch)
4. Measure the reground crankshaft journals for taper.
Maximum Taper: 0.01 mm (0.0004 inch)
5. Measure the reground crankshaft journals for size.
6. Refer to the undersize main bearing selection table in Engine Mechanical Specifications. Using the intersection of the measured journal size and the letters on the lower crankcase select the correct sized bearing from the table. Measure the oil clearance. If the oil clearance is incorrect install the next thicker bearing and recheck the oil clearance.