Main Bearing Removal
NOTE
Never move or lift the crankcase by grasping the cylinder studs.
The crankcase is too heavy to be carried in this manner and could be dropped.
1. Hold flywheel assembly to prevent it from falling out of left crankcase half. Rotate bottom end assembly in engine stand so assembly is upright and flywheel shafts are horizontal.
2. Carefully slide flywheel assembly out of left crankcase and place it in a clean safe place.
3. Remove thrust washer from outboard side of crankcase half by pulling it past oil seal. Set thrust washer aside for
inspection or reuse.
4. Remove oil seal from crankcase bore. Discard oil seal.
5. See Figure 3-124. Using a flat blade screwdriver, carefully lift edge of bearing retaining ring up out of its groove in crankcase.
6. Slide screwdriver tip around edge of bearing, lifting retaining ring up and out of groove. Do not damage lip of groove in crankcase.
NOTE
See Figure 3-125. If the ram of the press is wider than the head of pilot/driver (2), a suitable press plug will be needed in order to remove the main bearing.
7. Obtain CRANKCASE BEARING REMOVER/INSTALLER (Part No. B-45655) and REMOVER/INSTALLER SUPPORT TUBE (Part No. HD-42720-5).
8. See Figure 3-126. Place support tube (3) on press table with “A” end up. Note that support tube is stamped “A” and “B” to provide proper orientation.
9. With the outboard side of the left crankcase half facing upward, position main bearing bore over support tube.
10. Slide pilot/driver (2) through the main bearing into support tube (3).
11. Center pilot/driver under ram (1) of press. Apply pressure to pilot/driver until bearing is free.
12. Remove crankcase half, pilot/driver and bearing from support tube. Discard bearing.
Main Bearing Installation
NOTES
• Never move or lift the crankcase by grasping the cylinder studs. The crankcase is too heavy to be carried in this manner and could be dropped.
• Always replace sprocket shaft bearing inner race whenever left main bearing is replaced. See 3.28 CRANKCASE DISASSEMBLY AND REPAIR, Sprocket Shaft Bearing Inner Race.
1. See Figure 3-125. Obtain CRANKCASE BEARING REMOVER/INSTALLER (Part No. B-45655) and REMOVER/INSTALLER SUPPORT TUBE (Part No. HD-42720-5).
2. See Figure 3-127. Place a thin film of clean engine oil on outer diameter of new main bearing (4).
3. Place support tube (3) on hydraulic press table with the “A” end up.
4. With the inboard side of the left crankcase half facing upward, position main bearing bore over support tube.
5. Start new main bearing in bearing bore, letter side down.
6. Slide pilot/driver (2) through bearing into support tube.
7. Apply pressure to pilot/driver until bearing is lightly bottomed in main bearing bore.
8. Remove crankcase half and pilot/driver from support tube.
9. Install new retaining ring in bearing bore groove, being careful not to damage edges of groove. Make sure that retaining ring is fully seated in groove.
NOTE
If retaining ring will not fit into groove, the bearing may not be fully seated in the bore. Inspect bearing and bore. If necessary, remove bearing, clean bore and install bearing. Then install retaining ring.
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