S&S Cycle Super B Series Carburetor - Manual (Page 9)

8. Too much gear - not enough horsepower to pull gearing.
9. See “Notes on Intermediate and High Speed Jetting” below.
Notes on Intermediate and High Speed Jetting:
●
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 only as
secondary aid. We have found that different brands of
gasoline, gasoline additives, engine heat (due to ignition
timing), and type of plugs and heat range used distort plug
color drastically making plug reading difficult for average
tuner. Also, new plugs usually require road test of 10 miles
or more to properly develop color which means that quarter
mile tests may not be long enough and hence, not always a
good indication of carb jetting. It is best to use proven spark
plug combinations and to consult spark plug manufacturer if
you have questions. If one desires to become more
proficient at plug reading, Champion Racing Division has a
very informative booklet which may be helpful.
● If bike is used exclusively on drag strip where engine
temperatures vary, slightly richer jets may be necessary to
gain best performance. Larger jets or richer mixtures will
enable one to run colder engine which is sometimes
desirable. This is best determined by experimentation with
particular engine to be used.
● Cams and exhaust systems can make some engines difficult
to carburate. We have found that certain cams and exhaust
systems will cause poor performance at a specific rpm, and
attempts to carburate to correct this condition usually
destroys carburetion over the balance of the range. A
combination of cam overlap, reversion, and back pressure,
or even lack of back pressure can cause mixture dilution at
certain engine rpms. This dilution will cause engine
roughness or misfiring when engine is held in this range.
● Drag pipes - For knucklehead, panhead, shovelhead, and
ironhead Sportster
® model engines, 1-7/8” O.D. drag pipes
with straight cutoff end 28” to 30” long will work well with
almost any camshaft and/or other performance
modification. 2” O.D. drag pipes are not recommended for
any applications except very large competition engines. The
use of drag pipes is not recommended for Harley-Davidson
®
Evolution ® motors in street applications..
● Mufflered systems: A very good , economical street exhaust
system for Evolution ® and earlier engines as well, consists of
the stock head pipes with the cross-over tube and a set of
S&S low restriction mufflers. This system will typically
produce 10 hp more than drag pipes in the midrange. This
makes an ideal system for the street since the midrange is
where the vast majority of normal driving occurs.
NOTES - General Information
●
Carburetor body has seven drilled passages that are
permanently sealed with drive plugs. Do not attempt to
remove these plugs as irreversible damage to carburetor
may result.
● If throttle arm, part #11-2148, is removed from throttle
shaft, it must be reinstalled in wide open position with
throttle plate, part #11-2055, at 90˚ to the fully closed
position. See Figure B.
● Throttle plate, part #11-2055, should be checked annually
for signs of wear. Replace if necessary. If carb body needs
repair, use S&S repair kit, part #11-2903, #11-2914 or #11-
2909. If throttle plate is removed, be sure to reinstall it
correctly. See Figure C. Edges of- plate must fit flat against
carb throat.
● To insure proper seal in needle and seat assembly, float
hinge, needle lift and needle must work freely and must not
bind. If problem is suspected, remove bowl and check float
movement. If obvious misalignment, binding or sticking
occurs, remove and straighten and reinstall to attain free
movement. Reset float level and double check for free
movement. Float must not contact bowl gasket.
● Normal float setting is 1⁄32” and should be measured at end
of float opposite needle and seat assembly. To check this
measurement, turn bowl upside down and measure from
bowl gasket surface up to float.
● On rubber mounted engines, set float where it just misses
bowl gasket, part #11-2086, when fuel inlet needle is fully
closed and spring in needle is compressed. See Figure D. To
check, remove bowl and raise float until needle is in closed
position and spring in top of needle is compressed. Highest
part of float should be slightly (approximately 1⁄32”) below
bowl gasket surface. Float must not contact bowl gasket.
● When motorcycle is not running, fuel shutoff valve should
always be turned off to prevent possible leakage should
needle and seat not work properly.
● If an air horn is desired for drag racing, use S&S part #17-
0042. Be sure to shroud bowl vent.
● If you feel you have marginal fuel delivery through your
stock petcock, S&S recommends you try Pingel
® petcock, part
#19-0453 for big twins or 19-0454 for Sportster ® models
(requires nut #19-0455 for both). Tests conducted at S&S
have shown Pingle petcocks to provide more than adequate
fuel supply. If you require an in line fuel filter, use Pingel
#L1BLK1BLK40G, if room permits (filter is 3” long and
anodized black), or #S1P1P4OG, if room doesn’t permit (filter
is 1 1⁄2” long and polished aluminum).
As a convenience to our customers S&S stocks these Pingel parts.
S&S part #19-0453 - Pingel petcock #5211C for big twins
S&S part #19-0454 - Pingel petcock #31-6011 for Sportster
®
models
S&S part #19-0455 - Pingel nut #33-2001
S&S part #19-0457 - Small Pingel filter #S1P1P4OG
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