S&S Worldwide Motorcycle Accessories - Manual (Page 6)

8. Lower End Assembly (All)
NOTES:
●
All current production S&S ® Evolution ® Sportster ® model
flywheels are made from closed die, heat treated, steel
forgings. They do not have connecting rod thrust washers
like earlier S&S or stock flywheels, because present flywheel
material is harder than thrust washers previously used.
● S&S Sportster ® model style flywheels come with three
timing marks, "F", "R" and "TF". The "F" mark stands for
front cylinder 30° before top dead center (TDC). The "R"
mark is rear cylinder 30° before TDC, The “TF” mark is TDC
front cylinder. When "F" or "R" mark is placed in center of
timing hole it means that cylinder is timed at 30° before
TDC. We recommend that big inch Sportster
® engines be
timed at 30-32° before TDC rather than the stock 40°
before TDC. See Performance Notes, Ignition Timing.
● Usually S&S flywheels are balanced before leaving our
facility. Some customers prefer to do their own balancing or
to have another balancing shop do the work for them. This
is acceptable in most cases. However, we have had some bad
experiences with dynamically balanced flywheels that have
forced us to void our guarantee if flywheels have been
balanced in this fashion.
Flywheels assembled improperly prior to being dynamically
balanced may sustain irreversible damage to mainshaft and
crankpin tapers during actual balancing. S&S voids its
guarantee if flywheels have been balanced in this fashion.
● Many problems in assembling and truing flywheels can
be prevented by careful inspection of all parts used in
the assembly.
● Cleaning parts prior to and during assembly and keeping
parts clean after final assembly are imperative to minimize
contaminants that may circulate in oil and shorten engine
life. Many parts can be cleaned with soap and water first.
Then, reclean all internal parts and gasket mating surfaces
using high quality solvent that does not leave any harmful
residues. Be sure to read and follow manufacturer’s
instruction label before use. Use drills and compressed air to
clean all oil passageways of dirt, filings, etc. whenever
possible. During actual final assembly, recoat all internal
parts with high quality engine oil or assembly lube such as
S&S 51-9000.
Manufacturing chips, dirt and/or other contaminants
circulating in engine oil may possibly damage engine
components resulting in shorter engine life and possible
engine failure.
● Some solvents, degreasers, gasoline and other chemicals are
harmful to skin, eyes and other body parts. Many items are
flammable and present a fire hazard. Read manufacturer’s
instruction label for proper use. Use in well ventilated area
and wear protective clothing when using them to avoid
personal injury.
● Compressed air and particles dislodged by compressed air
are harmful to eyes and body. Wear protective goggles
when using compressed air and always direct air stream
away from body parts such as hands and eyes. Never direct
compressed air toward other people.
Perform following steps when assembling flywheels:
A.
Thoroughly clean all parts to be used. This includes
mainshafts, main bearings, connecting rods, rod
bearings, keys and flywheels including tapers and
key ways.
Burrs, dirt, filings, etc. left on flywheel assembly parts may
circulate in oil damaging other parts possibly causing
engine failure.
B. Inspect key ways and oil holes in flywheels for burrs and
remove if necessary.
NOTE: S&S does not recommend lapping tapers to remove burrs.
This practice tends to distort the taper by removing material
unevenly around the circumference. This makes flywheels
difficult if not impossible to true. In addition the lapping process
work hardens the surface of the taper. This hard surface makes
it very difficult to pull shaft or crankpin into taper. If crankpin
and shafts are not pulled fully into flywheel tapers, excessive rod
side play and assembly width may result. Lapped flywheel tapers
are also very difficult to resurface if repairs are ever needed.
S&S warranty is void if flywheel tapers are lapped.
C. Check keys in grooves of shafts. Key should be light
hand press fit in groove. If key is too tight in groove,
sand side key with fine sand paper on a metal plate or
other flat surface. Do not hammer key into groove.
Hammering tight key into groove may result in irreparable
damage to shaft.
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