Harley Davidson military motorcycle model 42WLA-Solo. Operation and maintenance Manual (August, 1942) — page 2

Truing and Sizing Main Bearing Races

(LAPPING ARBOR NUMBER 11954-40)

Before refitting worn main bearing, lap outer races to true them and remove any trace of wear shoulder at sides of roller paths. A race that is worn .0005" or more should be renewed.

When renewing main bearing races, heat cases around races. Heating expands cases slightly and less force is required to press old races out and new races in. New races, after installation, should also be lapped to smooth, true and align them, and to size them so that specified bearing clearance can be attained with roller sizes available.

When lapping main bearing races, right and left cases must be assembled and three or more studs securely tightened as in final assembly; this is to assure perfect alignment between left and right races in final assembly. Lap first one side and then the other, guiding lap by means of pilot bushing in opposite race. Adjust lap snugly in race and use only a light application of fine lapping compound. A loose lap and the use of excessive compound results in a tapered bearing surface.

Fitting Main Bearings

When fitting main bearings, the shafts that are to be used when flywheels are reassembled can be used as gauges with which to determine when bearings are fitted to correct clearance. Use the largest roller size that will allow shaft just noticeable shake in bearing. Bearing must not be fitted so tight that shaft has no shake at all. In making this check, all bearing parts must be perfectly clean and dry; oil in the bearing will take up some clearance and make bearing feel tighter than it is actually fitted.

After main bearing fitting is completed, crank-. cases with roller and retainer assembly can be set aside until flywheels are assembled.

Mainshafts (sprocket and pinion shafts) can now be fitted to their respective flywheels. Shaft tapers and flywheel tapers must be perfectly clean and tree of oil. Be sure keys are in place. Tighten nuts very tight (use manufacturer's wrench number

12645-29) and install lock washers. Lock washers can be installed either side up and either lock screw hole may be used. If lock screw can not be inserted with lock washer in any of its various positions, turn nut tighter rather than looser to bring lock washer to position where screw holes line up. Tighten lock screw very tight.

After right side (pinion) shaft is installed check oil passage through shaft and side of flywheel with compressed air, to be sure passage is open.



Fitting Connecting Rod Lower End Bearing



First give attention to flywheel washers (Item 19, Illustration 28). If washer in either flywheel is worn and grooved to any extent, it should be renewed. This hardened steel washer fits into recess in flywheel face around crank pin and takes side thrust of lower connecting rod bearing. Washer is a close fit in recess and is secured by punching flywheel metal tight against it at several points around washer.

To remove washer, it is ordinarily necessary to drill a small hole at the outer edge of washer to permit getting a pointed tool underneath and prying it out. This hole should be small and should be drilled only to slightly greater depth than thickness of washer. Drilling hole too large or too deep weakens flywheel and it may crack at that point. Before installing new washer, scrape outer edge of recess where metal was punched against old washer and thoroughly clean recess, as new washer must seat fully against recess bottom. If washer is carelessly installed and does not seat fully in recess, female (forked) rod is not likely to have required sideplay when flywheels are assembled.

Crank pin can now be fitted in left flywheel. Pin taper and flywheel taper must be clean and free of oil. Be sure key is in place. Tighten nut very tight (use manufacturer's wrench number 12731-29). Install lock washer. Washer can be installed either side up as it best matches lock screw hole. If necessary, tighten nut a trifle more to make lock screw holes match. Install lock screw and tighten securely.

Install right flywheel temporarily and check oil passage through pinion shaft, right flywheel and crank pin, with compressed air. Be sure this passage is open.



Truing and Sizing Connecting Rod Lower Races

(LAPPING ARBOR NUMBER 11944-X)



In lapping a set of worn rods, lap until no trace of wear shoulder is left at sides of roller path; also lap both rods to fit same size rollers.

When rod lower races are damaged or worn beyond truing up and refitting with largest oversize rollers, rods must be replaced with new or returned to the manufacturer for refitting with new lower races. It is not practical for other than the manufacturer to renew these races as they are distorted considerably when pressed into rods and the initial truing must be done with a grinder; lap is intended only for smoothing up and resizing races worn or not exactly the right size.

Refer to Illustration 24. Turn lap in lathe 150 to 200 R.P.M. When means of turning lap are not at hand, hold in vise and turn rod. Adjust lap to snug