S&S Cycle Sidewinder 3 5/8 Big Bore Cylinders for 1936–1999 Big Twins - Manual (Page 22)

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Final Assembly
A. Install manifold.
B. Install engine in frame.
C. Install engine head mount.
NOTE: Stock head mount will be short if you are installing S&S Sidewinder Kit with cylinders .0625" (1⁄16") or more longer than stock. If cylinders that are
1⁄16” or less taller than stock are used, modify stock mount. If cylinders taller than 1⁄16” are used, install S&S head mount, part #93-4054. This mount
is heavy duty and designed especially to provide support for tall, big inch engines. Its two piece design permits precise head to frame alignment
which reduces stress and potential head mount failure.
Improper mounting of engine in frame may cause engine to come loose resulting in damage and/or failure of engine motor mounts
and/or other engine mounting brackets.
16. Timing, Carburetion, Exhaust, Gearing & Break-in (All)
IgNITION TIMINg NOTES:
• See Step 8, “Lower End Assembly,” for explanation of S&S timing marks.
• S&S flywheels have timing marks that position pistons at 35° before top center, same as stock, when mark is in center of timing hole. Placing mark
to right side of hole or just entering hole advances timing almost 5°. Vice versa, if mark is just leaving hole, timing is retarded almost 5°.
• Maximum performance in early engines traditionally has been with timing set at 37° to 39°, but because of poor gasoline, detonation, etc. it is
advisable to stay with 35°. Some builders will even retard ignition timing slightly because of aforementioned problems, but if you do, watch heat
build-up. If there is any doubt, stay with factory recommended settings.
• Sidewinder® kits for Harley-Davidson® Evolution® engines—tests conducted on our dyno have indicated that the best horsepower will be produced
with timing set from 30° to 35°, depending on cylinder head design, compression ratio and type of fuel. S&S recommends that an aftermarket
electronic ignition with variable advance curves be used to allow adequate flexibility in tuning.
• Whatever ignition system is used, the best rule of thumb for most situations is to follow stock timing specs and watch for signs of detonation and/
or excessive heat.
• Ignition timing for engines with dual plugged heads should generally be retarded 5–8° from the stock setting. However, due to the large number of
factors involved, optimum ignition timing is impossible to accurately predict and must be determined for each engine by experimentation.
Improper ignition timing may cause excessive engine heat which may damage pistons and/or other engine components.
CARbuRETION NOTES:
• All S&S® test engines have been run with S&S carburetors. A Super E or Super G carburetor is recommended for most strokers. Consult carburetor
jetting instructions for specific jetting recommendations.
• If another type carburetor is used, it must be made to run rich enough so engine is not damaged. Other carburetor types are a personal problem
and we cannot answer questions concerning them. It is best to call carb manufacturer if you have any questions.
ExhAuST SySTEMS NOTES:
• To establish performance guidelines, S&S used 30" long stock diameter drag pipes on pre–1984 engines with good results. We suggest you try them
on these engines to establish a baseline to compare with other systems. Evolution engines are easier to carburate with muffled systems.
• You might ask the manufacturer of the exhaust system you are considering if he has had any experience with S&S strokers. Many systems are
made for looks with little consideration given to performance. Most stock systems and many aftermarket ones tried are too restrictive for good
performance. S&S offers slip-ons that work well with stock head pipes. These work very well in most situations and offer an inexpensive alternative
to a new exhaust system. Evolution engines should use a system equipped with a crossover pipe that connects front and rear header pipes.
CAUTION
CAUTION