S&S Cycle Super E and G Series Shorty Performance Carburetors for 1936-84 Harley-Davidson Big Twins and 1957-85 Ironhead Sportster Models - Manual (Page 14)

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6- No air cleaner used or air cleaner used is brand other
than S&S. Some air cleaners restrict air flow so that carb cannot
draw air as freely as needed. Also, some air cleaners may
obstruct bowl vent hole on inlet end of carb and change bowl air
pressure. See Picture 27.
Picture
27
NOTE: Bowl vent hole passage leads to cavity above fuel in bowl.
Passage equalizes bowl pressure and atmospheric pressure. If high or
low bowl pressure relative to atmospheric pressure develops, engine
may run erratically.
7- Insulator block between carb and manifold not used.
Heat transfer from manifold to carb may cause
temporary rich condition at idle and low rpm when
hot engine is restarted after being shut off for a short
time. Install insulator block to reduce heat transfer.
8- Air cleaner without element or air horn used without
removing bowl vent screw located in downward
facing boss on throttle cable side of carburetor body.
See Picture 15 on Page XX.
9- Poor engine condition - Leaking or sticky valves,
weak or broken springs, pushrod flex, improper
clearances for high lift cam, or defective camshaft
with improper valve timing.
10- Inappropriate exhaust system.
NOTE: S&S® has found that long, large diameter exhaust pipes, either
baffled or unbaffled, may present insurmountable tuning problems
when combined with S&S carburetor. If engine equipped with such
pipes does not respond to normal tuning procedure, contact exhaust
manufacturer for his tuning suggestions or call S&S for exhaust
recommendation.
11- Too much gear- Horsepower insufficient to pull
gearing.
12- Incorrect float setting - Setting float too high will
cause engine to run rich at idle and at low speeds,
and may prevent jet change from correcting over rich
mixture. Float setting too low will cause poor off idle
response and may cause mixture to "lean out" at high
speed or when motorcycle leaned over in curve due to
insufficient fuel reserve in bowl. See General
Information on Page XX for float jetting instructions
and specifications.
13- Fuel standoff - Occasionally, fuel may be seen misting
out carburetor at full throttle when air cleaner is
removed. Because carburetor is simply a conduit
through which air and fuel enter engine, it does not
cause fuel standoff. Usual cause is cam timing and
exhaust reversion.
14- Overflow hose missing from the carb bowl can cause
engine to miss and break up at high speeds. This
problem will more than likely not occur on the dyno
because the motorcycle is not moving through the
air.
Adjustable Air Bleed for Super E and G Carburetors
The main air bleed passage in S&S Super "E" and "G"
carburetors is fitted with a replaceable .040" jet. See Picture
26 on Page XX. The replaceable jet allows changing the size of
the main air bleed. Carburetors with this feature can be
identified by a serial number that begins with the letter E or
higher.
NOTES:
• The standard .040" diameter air bleed is the optimum size
for most engine combinations, and should not be changed
under most circumstances, regardless of intermediate and
main jet selections.
• Changing the main air bleed size should be done only after
determining a mid range driveability problem cannot be
corrected by changing the intermediate and main jets.
• For tuning the main air bleed, S&S® recommends an initial
increase from the standard .040" jet to a .048" jet as a
starting point. Available jets and part numbers are listed in
the S&S
catalog.
• It is never necessary to reduce the size of the main air bleed
below .040".
• Shifting the start of main jet operation to a point higher up
the rpm scale can lessen the effects of mid rpm driveability
problems caused by mismatched cam and exhaust
systems, but will not allow the engine to perform as well as
it would with a well designed exhaust system.
INTERMEDIATE AND HIGH SPEED NOTES:
• Carburetor jetting and spark plug color - While spark plug
color may be used to help determine carburetor jetting,
S&S recommends that our instructions be used as primary
jetting guide and that plug color indications be used as
secondary aid. Different brands of gasoline, gasoline
additives, engine heat, type of plugs, and spark plug heat
range can effect plug color making plug reading difficult
for average tuner. Also, new plugs usually require road test
of 10 miles or more to properly develop color. This means
that quarter mile tests may not be long enough to be a
good indication of carb jetting. It is best to use
recommended spark plug type and to consult spark plug
manufacturer with questions.