Illus 53 Truing Flywheel Mainshafts

Truing Flywheels

Bear in mind that, while a straight edge across rim faces is used when assembling flywheels to keep them as near as possible true with each other, final truing is a matter of truing sprocket shaft and pinion gear shaft to perfect alignment with each other, rather than truing flywheel rims. Install wheel assembly in truing device (Harley-Davidson truing device, Part No. 11962-X) and adjust so that centers are just snug (wheels must turn freely). If flywheel assembly is either loose between centers or is squeezed, indicators will not indicate accurately. Indicators should be adjusted as closely as possible to flywheels, and so that pointers rest about in the middle of graduated scales (see Illus. 53).

Turn flywheels and observe the movement of indicator pointers. Movement of pointers toward flywheels indicate high points of shafts. Find highest point of each shaft and chalk-mark flywheel rims at those points. Loosen centers slightly, just enough so it can be detected that flywheel assembly is a trifle loose. Turn high point of first one flywheel and then the other to the top and strike rim of wheel one or more sharp blows with a lead or copper hammer. The number of blows required and how hard they should be depends, of course, on how far shafts are out of true. Remember that centers should be loosened slightly before striking flywheels. However, they should not be loosened to the extent of allowing flywheels considerable play between centers, as making them very loose is likely to result in broken or damaged centers.

After striking wheels with hammer as explained above, readjust centers to just snug and aqain turn wheels and check with indicators. Repeat the truing operation until indicators show within .001" of true. Each graduation on indicator scale is approximately .002"; therefore, when shafts are true within requirements, neither indicator will move more than about one-half graduation.

In the case of a flywheel assembly that is considerably out of true and which cannot be trued up by following the procedure described, it may be due to crack at one of the tly wheel shaft holes or a damaged and enlarged tapered hole. If used sprocket and pinion shafts are assembled in flywheels, it may be due to one of these shafts being worn considerably oui of round at the point where indicator takes bearing against it.

Assembling Crarikceses

Flywheels are now ready to be assembled into crankcases which have already been given due attention as concerns main bearing fitting (see "Fitting Main Bearings," Page 60). A strong rack or box with an opening about 8" x 8" and at least 4" deep should be available, on which to place right crank-case on its side. O.H.V. Engine: With pinion gear shsft bearing spring ring engaged in groove in roller rare, install b«?ai;.->g v/asher, bearing assembly and bearing spacer as shown in Blus. 62. Side Valve Engine: With pinion gear shaft beanng spring ring enoeaed in qroove in idle: race, install bearing W5.f'.:er and bearino ■■■¿sembiv in the order shown

A11 Models: Select two flywheel thrust collars and install one on each flywheel hub. Be sure they register on dowel pins and seat fully against wheel faces. These collars come in various thicknesses (.066" to .102" in steps of .004") to permit adjusting flywheel endplay between crankcases. The only way to determine exactly what collar thickness is reguired is to try one set and then another until the correct endplay is attained. The average thickness of collars used in new engine assembly is about .086". Both collars should be approximately the same thickness in order to keep flywheels centered in crankcases and connecting rod upper ends centered between piston pin bosses.

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