S&S Cycle Super Stock Cylinder Heads for 1966–1984 Shovelhead Models - Manual (Page 8)

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C. Install pushrods with cover assemblies. Adjust pushrods according to manufacturer’s instructions and install cover retainer clips.
D. Install carburetor, air cleaner, and support bracket according to manufacturer’s instructions.
Fuel supply and overflow lines must not contact hot surfaces which could melt line, resulting in gasoline leakage and possible fire hazard.
All clamps must be tight to prevent gasoline leak. Refer to warnings on page 2 concerning gasoline hazards.
E. Using gaskets, lock washers, and socket head cap screws provided, install exhaust. Exhaust system must also be bracketed to frame for
adequate support.
F. Gap and install spark plugs. Heads accept standard 14-1.25mm, 3⁄4" reach sparkplugs. Camside sparkplug in dual plug heads will usually be
same heat range as other.
G. Start motorcycle and observe for gasoline and oil leaks.
6. Tuning
A. Carburetor
Because S&S® heads will probably flow significantly more air than heads removed, carburetor may require larger jets for best performance.
Consult carb manufacturer’s instructions for tuning procedure.
B. Ignition Timing
No adjustment should be required for single spark plug cylinder head. Overall ignition timing should be retarded 5-10 degrees in most dual
plug applications.
In general, excessive ignition advance will cause engine to kick back against starter during start-up and “buck” when ridden at steady speed
with partial throttle. An advanced condition can also cause pinging or ignition knock and possible piston damage. Some symptoms may not
be noticeable if an electronic ignition with a “soft” advance curve is used. Excessive ignition retard causes sluggish performance and severe
overheating with possible subsequent damage to the engine, and must also be avoided. Immediate or rapid exhaust pipe discoloration is
usually a sign of retarded ignition timing.
Pinging or ignition knock can be an early sign of detonation and possible impending engine damage. Should pinging occur, the throttle
must be backed off and the cause determined and corrected. Excessive retard is less obvious but equally destructive. For that reason,
final timing should be confirmed with a timing light or other accepted procedure.
Incorrect ignition timing can cause extensive engine damage not covered under warranty.
7. Break-in
Because of tight fit of new valves and guides, engine should be ridden 1000-2000 miles before subjected to excessive heat caused by traffic,
heavy load, high speed operation, etc. If rings or pistons replaced, break in as follows:
A. First 50 miles are critical for new rings and pistons. Most engine damage occurs during this period. Keep heat down by avoiding heavy traffic
and not exceeding 2500 RPM or approximately 50-60 MPH, depending upon gearing, during this time. Vary speed and do not lug engine.
Change oil and filter at 50 miles.
NOTES: S&S recommends that the cylinder base nuts and head bolts should be retightened after engine has been run and reached normal operating
temperature.
B. For next 500 miles, engine may be taken to 3500 RPM or approximately 60-70 MPH (depending upon gearing) for brief periods. Speed
should be varied, and lugging and heavy traffic avoided. Change oil and filter at end of first 500 miles.
C. Modest increases in speed are permissible during next 1500 miles. Engine should not be given full throttle, and heavy loads such as trailers
and sidecars avoided. Some operation at in-town speeds (40-45 MPH) is recommended, although lugging and heavy traffic should still be
avoided. Change oil and filter at 500 mile intervals until 2000 miles.
D. The following is mandatory at 2000 miles and thereafter: HAVE FUN! Oil and filter should be changed every 2000 miles after break-in, more
often if oil appears dirty or engine is subjected to extreme temperatures or dusty conditions, ridden for only short periods of time, or
frequently operated in heavy traffic.
WARNING
CAUTION
WARNING