Before installing the crankshaft, the main bearing oil clearance must be checked. Position the left crankcase section on a workbench with the bearing saddles facing up, and wipe the main bearing surfaces of the crankcase with a clean lint-free cloth to ensure they are spotlessly clean. Clean the back sides of the main bearing inserts and lay one bearing half in each main bearing saddle in the crankcase on the workbench, with the other bearing half from each set in the corresponding location in the remaining crankcase section. Ensure the tab on the bearing insert fits into the recess in the crankcase without hammering the bearings into place or nicking or gouging the bearing faces, and do not use lubrication at this time. Clean the faces of the bearings in the crankcase and the crankshaft main bearing journals with a clean, lint-free cloth. Once the crankshaft is clean, carefully lay it in position in the left crankcase section on the workbench. Trim three pieces of Plastigage so they are slightly shorter than the width of the main bearings, and place one piece on each crankshaft main bearing journal, parallel with the journal axis. Clean the faces of the bearings in the right crankcase, then carefully lay it in position without disturbing the Plastigage. Install and tighten the crankcase bolts, ensuring not to rotate the crankshaft at any time during this operation. After tightening, remove the bolts and carefully lift off the right crankcase section without disturbing the Plastigage or rotating the crankshaft. Compare the width of the crushed Plastigage on each journal to the scale printed on the Plastigage container to obtain the main bearing oil clearances, which should typically fall between 0.0015 to 0.0023 inch (0.038 to 0.058 mm). If the clearance is incorrect, double-check that you have the right size bearing inserts, recheck the crankshaft main bearing journal diameters, and ensure no dirt or oil was present between the bearing inserts and the main bearing caps or the block when the clearance was measured. Remove all traces of the Plastigage from the bearing faces or journals using a wood or plastic tool to prevent damage to the bearing surfaces. Carefully lift the crankshaft out of the crankcase, clean the bearing faces, and apply a thin layer of engine assembly lube to each of the bearing faces in both crankcase halves, including the thrust bearing faces. Carefully lay the crankshaft in the left crankcase section, ensuring the connecting rods are directed into the cylinder bores. Finally, reassemble the crankcase halves.