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Coming back soon.

Sorry no more motorcycle content until my broken arm heals.

Transmission Work PT2

Transmission is leaking real bad again lets see whats inside.

I lost some caged needle bearings causing the countershaft to wobble around.

#chopcult #harley #harley problems #shovelhead

Out the transmission comes.

#shovelhead #chopcult #harley problems

Unfortunately the transmission really started leaking after 500 miles.

#shovelhead #chopcult #harley #harleyproblems

Old school cool.

#old school chopper #chopcult #harley

I would not be keeping these exhaust pipes. There were issues with the valve job I had done.

#chopcult #finishedproduct #harley #shovelhead #old school chopper

The heart of the beauty.

#chopcult #shovelhead #old school chopper #harley

It’s all coming together.

#shovelhead #realchoppers #old school chopper #chopcult

The piston and needle of a SU Eliminator I in action. If you look closely after the first rev before the piston comes down the butterfly plate is visible. The spray coming out of the carburetor is fuel standoff. The fuel flow flowing backwards as the intake-ports are closed when the fuel gets there.

The Su Eliminator I and II Tuning Guide PT 1

Su carburators were advanced tech in the 1970′s and found only on imported. They used the constant velocity principle which at the time was very advanced compared to the butterfly with fixed venturi carbs that every engine used. The piston in the SU has a metering needle attached to it and the piston is actuated by manifold vacuum. As the episton goes up and down the needle either blocks or exposes the main-jet orifice. Thus allowing or denying the engine fuel in relation to the engines rpm. This was highly advanced in the 1970′s and still is today.

Manifold Vacuum is important. In simple terms its the force that draws in fuel from the carburetor. If you open the plate on a butterfly carb too quickly you get a lean pop out of the carb. Why the lean pop? The manifold vacuum wasn't strong enough to draw fuel from the intermediate or main jet. As the butterfly was opened air rushed in to the engine without picking up fuel leaning out the fuel mixture. The size of the venturi or carb throat as alot to do with this as there is plenty of space for air to flow past the butterfly without picking up fuel. Modern butterfly carbs Like the S&S Super E have “acceleration pumps” to overcome the pop. These pumps squirt fuel down the throat of the carb right when you begin to open it. That squirt drives up the rpms and thus the pistons create a stronger vaccum to suck fuel from either the intermediate or main jet. When you open the back butterfly on a SU eliminator the piston is exposed to manifold vacuum and more of the needle is exposed allowing the main jet to give the engine more fuel. However this opening doesn't have the effect of drawing in a massive amount of air as the piston has to move to let air in exposing the needle and jet. As the piston moves up it creates a venturi and as the air rushes past the piston created ventrui it picks up fuel as the venturi is perfectly sized relative to the engine RPM. Thus the SU doesn’t waste important manifold vacuum.