Fitting Sprocket Bearing

If Timken tapered roller bearings and races pass visual check and have no apparent wear, the same set may be reinstalled. Make certain all parts of bearing are installed in exactly the same order they were removed. If any part of bearing assembly is worn, entire assembly should be replaced.

ASSEMBLING CRANKCASE (Fig. 3E-2)

Install flywheel side outer race snap ring (10) in case. Using arbor press and Outer Race Press Plug, Part No. 97194-57 press outer races (12 and 14) and bearing spacer (13) into crankcase bushing one at a time. Press the races into the case with widest ends outward to match taper of bearings. Be sure the first race bottoms on the snap ring and each successive part tight against the one before.

Install bearing (16) spacer (11) on sprocket shaft using bearing tool. Press the parts on using sprocket shaft spacer (11) as a pressing spacer only. Turn tool screw onto sprocket shaft thread and tighten securely. Remove tool handle and slip the bearing

Figure 3E-15. Lapping Pinion Shaft Main Bearing Race

with left case bearing, and to attain a size compatible with roller sizes available.

LAPPING ENGINE MAIN BEARINGS (Fig. 3E-15). Secure right and left crankcase halves with three crankcase stud bolts (top center and bottom left and right). The sprocket shaft bearing outer races and large spacer must be installed in left crankcase.

Assemble lapping arbor to lapping handle and assemble guide sleeve to sprocket shaft bearing bushing. Sleeves for use with tapered bearing, are assembled to case with bearings and small spacer collar. Turn sleeve parts finger tight.

Insert lap shaft with arbor assembled through pinion bearing bushing and into guide sleeve. Tighten arbor expansion collars using a length of 5/32 in. rod as spanner until arbor begins to drag. Do not adjust arbor snug in bushing or bushing will "bell," a condition where hole is larger at ends than it is in the center.

Withdraw arbor far enough to coat lightly with fine lapping compound. Do not apply a heavy coat. Reposition lap in bushing and turn handle at moderate hand speed. Work lap back and forth in bushing as it is revolved to avoid grooving and tapering.

At frequent intervals, remove lap from crankcase, wash and inspect bushing. Lapping is completed when entire bushing surface has a dull, satin finish rather than a glossy, smooth appearance. If necessary, flush off lap in cleaning solvent, air dry and apply fresh, light coat of fine lapping compound.

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