S&S Cycle Cylinder Heads for Harley-Davidson Twin Cam 88 Engines - Manual (Page 6)

If throttle does not return to fully closed position when
released, it may inadvertently stick open possibly causing loss
of control of motorcycle and personal injury to you or others.
NOTE - Fuel needle and seat assembly must completely shut off
fuel supply entering bowl. Fuel line connections must not leak.
Unwarranted gasoline leaking by fuel inlet needle may flood
engine causing damage to components.
Unwarranted gasoline leaks at fuel line connections and/or
past inlet needle may flood engine and overflow on
surrounding area creating fire hazard.
4. Engine Break-In Procedure
NOTES:
G S&S
® engines are designed for high performance and as such
are not as tolerant of inadequate break-in as stock or lower
performance engines. Correct break-in will assure longer
engine life and will prevent unnecessary engine damage.
Engine damage caused by improper break-in is not covered
under the S&S warranty.
G If new pistons have not been installed, only steps A, B, and C
are required.
G If new pistons have been installed, all break in steps are
required.
A. Initial start up. Run engine approximately one minute
at 1250-1750 rpm. DO NOT crack throttle or subject to
any loads during this period as head gaskets are
susceptible to failure at this time. During this time check
to see that oil pressure is normal, that oil is returning to
the oil tank, and that no leaks exist.
B. Shut off engine and thoroughly check for any leaks or
other problems. Let engine cool to the touch
C. After engine has cooled, start up again and allow the
motor to build some heat. Engine should be run no
longer than three to four minutes. When the cylinders
become warm/hot to the touch (approximately 150°)
shut the motor down and let it cool to room temp.
Follow the same cautions as for the initial start-up, and
continue to watch for problems.
D. Repeat this procedure 3 or 4 times. Each successive time
it should take slightly longer to warm up and you can
increase the temp slightly each time (+10°). You can be
more liberal each time with the rpm, gently vary rpm
continuously from idle up to 2500 rpm in the final cycle.
Don’t be too concerned with final carb settings at this
time because idle speed and mixture cannot be correctly
set until the motor reaches full operating temperature.
The motor should not reach that temperature during
these cycles. Do not allow engine temperature to
become excessive. After completing the initial series of
heat cycles, the engine is ready for final carburetor
adjustments and the 500 mile engine break-in process.
E. The first 50 miles are most critical for new rings and
piston break-in. Engine damage is most likely to occur
during this period. Keep heat down by not exceeding
2500 rpm. Avoid lugging the motor, riding in hot
weather or in traffic. Vary the engine speed. Do not lug
the engine. We recommend changing the oil at 50 miles.
F. The next 500 miles should be spent running engine
no faster than 3500 rpm or 60 mph. Avoid
continuous steady speeds, and do not lug the engine.
Vary engine rpm. We recommend changing the oil
again at 500 miles.
Lugging or running engine prematurely at sustained high rpm
may result in damage to pistons and other engine
components. S&S voids its guarantee if engine is not broken
in properly.
G. For the balance of the first 1000 miles the motor can be
run in a normal but conservative manner. You can be
more liberal with the rpm range and motorcycle can be
operated at normal highway speeds. Avoid overheating
or putting any hard strain on the engine: no drag
racing, dyno runs, excessive speed, trailer towing, or
sidecar operation.
H. After 1000 miles, verify carburetor jetting and
adjustment. Change the engine oil. Motorcycle can now
be operated normally.
5. Performance Notes
G Ignition system - For Harley-Davidson
® Twin Cam 88 ® engine
kits, we recommend that an aftermarket or high
performance ignition module be used. Engines built with
S&S kits have higher than stock compression ratios,
performance cams, and in some cases cylinder heads with
combustion characteristics that are different from stock.
These and other factors effect the ignition requirements of
the engine. Programmable ignition systems allow ignition
maps to be optimized for a specific application, but should
be programmed by a qualified technician. Consult the
ignition manufacturer for recommendations regarding use
of a specific ignition system with large displacement, high
compression engines.
G Spark plugs - Use spark plugs and wires that are compatible
with the ignition system. Dual plug installations in S&S Super
Stock
® heads are not generally necessary.
G All S&S test engines are run using S&S carburetors. S&S
Super E and G carburetors are recommended for most
applications with the Super G being used more often on
larger displacement, freer breathing engines with higher
compression ratios. Typically, engines equipped with S&S
heads require the same or slightly leaner jetting than those
engines fitted with stock heads. Consult the carburetor
jetting instructions for specific jetting recommendations.
G If a brand of carburetor other than S&S is used, it must be
made to run rich enough to operate properly and to prevent
engine damage. Any technical questions regarding use and
adjustment of carburetors other than S&S should be
directed to the manufacturer. This includes S&S carburetors
that have been modified by a third party.
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CAUTION
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CAUTION
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