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If the pistons LOOK good, measure the diameter across the skirt, and compare it to spec's. Check the piston ring grooves for wear. If the sleeves are badly worn (MAJOR ridge at the top of ring travel, and diameter beyond wear limits), you'll need to replace them, a lesser ridge must be removed with a ridge reamer, or you risk breaking the new rings. If re-using the sleeves, use a glaze breaking hone to make a nice new crosshatch pattern to help the new rings seaat. Check the old bearing inserts for undersize markings. (Originals will be labelled STD for standard, undersize will be labelled .001, .002, .003, .010, .020, etc.). Then mic. the crankshaft journals, and verify how far it is from original or specific undersize specs.. Be sure to check the jounals for "out-of-round", as they tend to wear "eggshaped". If the crank is within wear limits, and has no deep grooves, scratches, or roughness, order new bearings according to the measured rod and main journal diameters. When assembling with new bearings, verify the oil clearances with Plastigage.
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