Stage Three
An 80 CID engine using stock Harley-Davidson cases,
cylinders and heads with 95.3 Ft.Lbs. of torque at 4700 rpm's is not your usual cruiser.
The maximum power is reading just over 95 Horsepower at 5700 rpm. The motor was
specifically tuned for DYNO SHOOTOUTS and DRAG RACING. The power is very strong between
4000 and 6000 RPM. Outside of this RPM range, the engine power drops rapidly. The engine
in this particular state of tuning, does not make a pleasant street motor. The very narrow
power band limits low speed cruising. In this case, low speed is anything under 3000 RPM's
and you have to consider the decibel level of the exhaust. The noise level of an uncorked
SuperTrapp pipe is only marginally lower than a top fuel drag bike. This bike is LOUD!!
The street version of this engine combination is the
Stage Three Round Two engine with 85HP. Replacing the velocity stack with the Mikuni Air
Cleaner and adding the SuperTrapp exhaust system baffles drops the horse power by 10HP,
but changes the personality of the engine completely. The SuperTrapp exhaust system with
18 disks and an open end cap has a pleasant engine sound, without being excessively loud.
The engine produces smooth, if not exhilarating acceleration from any speed with just a
twist of the wrist. The engine is quite content moving the bike from stop light to stop
light, or for taking a brisk ride down a deserted country road.
Extensive testing with a variety of other exhaust
systems was performed. Straight pipes at 22 inches, 30 inches and 36 inches were tried
with no additional horse power gains. A special set of adjustable 3 step pipes was also
tried at a variety of lengths with no improvement over the SuperTrapp exhaust system. The
most promising exhaust system in matching the power produced by the SuperTrapp 2-1 system
was the Cycle Shack slash cut pipes. The testing of the Cycle Shack pipes without the
baffles yielded just under 92 horsepower. The Cycle Shack pipes produce a smooth
horsepower curve, but do not product the high torque of the SuperTrapp. One curiosity of
the test was that the Cycle Shack pipes did not exhibit the rapid drop in power seen when
using the SuperTrapp exhaust.
Year: 1994
Model: EVO
Bore: Stock
Stroke: Stock
Displacement: 1340cc
Cases: 1997 H-D
Assembly: Owner
Crankshaft and Flywheel: H-D
Heads: H-D
Intake Valves: Stock Diameter
Exhaust Valves: Stock Diameter
Valve Springs: Crane
Porting: CycleRama, Pinellas Park, FL.
(813) 546-0889
Compression Ratio: 10.5:1
Pistons: JE 10.5:1
Cam: 3Suns - 252° Duration - .550 Lift
Pushrods: Crane Time-Savers
Carburetor: Mikuni HSR-42
Carburetor Jetting Information: 175 Main
Manifold: Mikuni
Air Cleaner: Velocity Stack
Ignition: Crane HI-4
Ignition Timing: 32° BTDC
Coil: Crane
Pipes: RevTech SuperTrapp 2-1 open pipe
Dyno Tuning Facilities: CycleRama,
Pinellas Park, FL. (813) 546-0889
