Connecting Rod Bushing

When connecting rod bushing is tight in rod but is worn to excessive pin clearance (.002 in. or more) it is possible to service by reaming oversize and fitting an oversize pin. However, it is recommended that a new bushing be installed and reamed to fit a standard pin, except when piston to be used had previously been fitted with oversize pin, or pin is loose in bosses, necessitating fitting with an oversize pin. The objection to fitting upper end oversize is that considerably more time is required for the job. New pistons, standard or oversize, obtained from factory are supplied correctly fitted with standard pin, and may be installed in a short time if the rod bushing is already reamed to standard size. If bushing has been reamed oversize, either a new bushing must be installed and reamed to standard size or piston must be reamed oversize to fit an oversize pin, which involves extra time.

The oil ring is a full width slotted oil control ring using a spring expander.

Figure 3C-9. Assembling Rings with Ring Expander

To check ring gap, place a piston in cylinder with top end of piston about 1/2 in. from top of cylinder. Place ring in cylinder bore squarely against piston and check gap with thickness gauge (see Fig. 3C-7).

When replacing bushings in connection with only a top overhaul, use Harlev-Davidson special tools as shown in Fig. 3C-10, Bushing Tool, Part No. 95970-32A and Connecting Rod Clamping Fixture, Part No. 95952-33. Be careful to start new bushing with oil slot in alignment with oil slot in rod.

Ream new bushing to size with Special Reamer, Part No. 94800-26. A properly fitted pin should have .001 in. clearance; with this clearance, pin will have just noticeable shake in bushing. Fitting tighter is likely to result in a seized pin or bushing loosened in rod. Oversize piston pins are available .002, .004, .006 and .008 in. oversize.

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