S&S Cycle Big Twin Engines with 3-1/2 and 3-5/8 Bore Crankcases and Special Application (SA) 4 Bore Crankcases - Manual (Page 6)

4. Install driveshaft gear key and snap ring.
NOTE - Be sure drive shaft key and snap ring are installed
properly, paying particular attention to snap ring. If not installed
correctly, “sprung,” or otherwise damaged, snap ring may come
off or allow gear key to come out. See Pictures 12A & B.
Loss of oil pump drive gear snap ring or key will result in
disengagement of oil pump causing loss of oil pressure and
extensive engine damage.
5. Loosely install 2 ea. 1/4-20 x 1-1/2” top oil pump bolts,
followed by pump cover and 4 ea. 1/4-20 x 2-3/4” mounting
bolts. Do not tighten at this time.
NOTE - 1/4-24 bolts supplied with oil pump kit are not used in
S&S
® engines.
6. While turning oil pump drive gear to check pump for
binding, gradually tighten 4 2-3/4” bolts in X-pattern to final
spec. of 8-10 ft-lbs. See Picture 13. Carefully tighten short
bolts “by feel” with thin box end wrench.
7. Prime pump by removing oil pump check valve ball assembly
(See illustration on page 15 in Oil Pump Instructions) and
injecting clean motor oil into pump supply fitting while
turning oil pump drive gear. (A large plastic squeeze bottle
works well for priming pump.) Replace check ball, spring,
and cap after oil fills check valve cavity.
INSTALL PINION GEAR, SPACER AND NUT
(All Unassembled)
1. With chamfer on oil pump drive gear facing in towards
shoulder on pinion shaft (See Picture 14), install oil
pump drive gear and key on pinion shaft, followed by
drive gear spacer.
Installing gear backwards can result in a stress riser and cause
shaft to break.
2. Apply thin film of red Loctite ® #271 to pinion shaft taper and
threads. Install pinion gear, key and nut on pinion shaft and
tighten nut to 50 ft-lbs. See Picture 15. S&S Connecting Rod
Checking Pin, part #53-0002, can be used to prevent
flywheels from turning as pinion nut tightened on shaft.
6
Picture 12B (Correct Installation) Picture 13
CAUTION
Picture 14 (Note Chamfer) Picture 15
CAUTION