S&S Cycle 124 Twin Cam Style Assembly And Installation Instructions Manual - page 16
2. Engine
break-in
1. Closely monitor engine for excessive heat
build-up. Do not allow the engine to idle for
long periods of time. Be especially watchful
when air temperatures exceed 90 degrees.
Slow speed operation in urban areas during
the summertime is especially hard on engines..
Temperature for engine oil should be between
180º - 240º F. If engine oil temperature stays
above 220º F, and correct ignition timing has
been verified, S&S Cycle suggests that an oil
cooler be installed. Do not run engine under
conditions where oil temperatures continue to
remain high.
2. For the first 50 miles ride the motorcycle in a
very conservative manner. 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.
Change the oil at 50 miles. This will remove the
heavy accumulation of break in residue from
the oiling system.
3. The next 500 miles should be spent running
engine no faster than 3500 rpm or 60 mph.
Correct any obvious ignition or fuel problems, if
present. Avoid continuous steady speeds, and
do not lug the engine. Vary engine rpm.
change the oil again at 500 miles.
CAUTION – Lugging or running engine prematurely at
sustained high rpm may result in damage to pistons
and other engine components. S&S voids it’s
guarantee if engine is not broken in properly.
4. 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.
5. After 1000 miles, verify Ignition and fuel
system settings and adjustments. Change the
engine oil. The break in process is complete.
L. Tuning Guidelines
Ignition timing and carburetor jetting are responsibilities
of the customer. If not thoroughly familiar with these
procedures, contact a professional mechanic.
1. Exhaust
Systems
Muffled exhaust systems.
If you have an existing 2-into-2 system that uses
slip-on style mufflers, whether it is an OEM or an
aftermarket system, we recommend the new S&S
slip-on mufflers. S&S dyno tests achieve almost 8
more horsepower and 5 ft. lbs. of torque on a stock
Twin Cam 88 engine using stock header pipes and
S&S slip-on mufflers, and S&S Super Sidewinder
engines have produced 1-1.1 horsepower per
cubic inch using stock style exhaust and S&S slip-
on mufflers. These mufflers will allow your engine
produce more horsepower and torque than
straight-through drag pipes in street and highway
driving, and work equally well on both stock and
large displacement engines.
Drag pipes
While drag pipes can be used with good results to
achieve top end horsepower, they are generally not
recommended for street applications. Carburetor
adjustment and jetting is generally easier for
engines with muffled exhaust systems.
2. Gearing
Gearing depends on the total weight of the
machine and rider, the size of the engine, cam,
exhaust system and type of riding. Most high
performance engines, and particularly those with
larger displacements, are capable of pulling more
gear. We suggest you break the engine in with
stock gearing to minimize the load on the engine.
After the engine is broken in, you will have a better
feel of its potential and can change gearing
accordingly.
The following formula will determine final drive
gear ratio:
Engine Revolutions Per One Revolution of Rear Wheel=
(Clutch Sprocket*) x (Rear Wheel Sprocket*)
(Motor Sprocket*) x (Trasmission Sprocket*)
*Number of teeth on each sprocket
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