Operating instructions

5-8
5-31. Hardened steel bushings in the crankshaft
blades may be removed and replaced if excessively
worn. It may be necessary to chill the old bushings to
free them. New bushings must be chilled before
installation with a suitable drift, and the holes must be
smooth. No finishing operation is required for the new
bushings, since they are made to final dimensions.
They must be driven in to the same positions as the
original parts.
NOTE
Crankpins and crankshaft main journals
may be reground to the allowable 0.010
inch undersize.
CAUTION
Crankshaft counterweights are matched in
pairs with a maximum weight variation of 2
grams, and the complete crankshaft and
counterweights assembly is dynamically
balanced. As a result, ifeither
counterweight is damaged it will be
necessary to discard both on that cheek
and to procure a matched pair for
replacement.
5-32. IDLER GEAR. Replacement of excessively
worn idler gear bushings is not recommended, because
a special fixture is required to hold the gear during the
boring operation, in order to maintain the necessary
concentricity of the bushing hole and the gear pitch
circle.
5-33. MAGNETO AND ACCESSORY DRIVE
ADAPTER ASSEMBLY. If the magneto and
accessory drive adapter bushing must be replaced, it
may be driven out with a 0.92 inch diameter drift
while the adapter boss is supported on a 1.12 inch 1.0.
ring; however, this procedure involves some chance of
scoring the adapter bore. A safer, though more
laborious procedure is to turn down the bushing flange
to the body diameter (0.942 inch) and to bore out the
bushing to a thin shell which can be collapsed. If this
method is used, take care not to cut into the end of the
adapter boss or to mark the adapter bore. Press in a
new bushing with an arbor press after dipping it in
FIGURE 5-8. CONNECTING ROD AND BUSHING DIMENSIONS.