1. Put the crankshaft in a vise with soft jaws, with the left drive shaft pointing up.

2. Replace the shims on the drive shaft that were removed during disassembly.

3. Install the new bearing on the drive shaft and push it down as far as possible with your fingers.

4. Place a length of pipe over the drive shaft and against the inner race of the bearing (see Figure 1).

5. Tap the pipe with a hammer until the bearing seats against the shims.  Be sure not to exert any force against the outer bearing race.
 

NOTE: The left main bearing has a "C3" stamped on the outer race (see FIGUREs 2 AND 3).  Be sure this mark is on the bearing installed on the left shaft.

6. Clean the engine cases thoroughly with solvent and dry with compressed air.  Check the bosses carefully for wear or damage from the previous bearings.