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Tuesday 6 June 2023

American Prime Manufacturing (APM)

SU Rebuild Service - Authenticity in Spades

Last year we featured a complete SU Eliminator II carburetor rebuild kit that was introduced by American Prime Manufacturing (APM) in California - "Back to the Future", February 2022/#271.

Now, news comes to us from Ben Kudon that APM is offering a professional factory rebuild service - "to take your SU from comatose to like new!"

For over 50 years, the SU carburetor in modified form, known as the SU Eliminator II, has been a 'go to' for early American V-twin motorcycles. Ben Kudon says that "it provides smooth, even power and torque throughout the entire power band, with excellent cold-start characteristics and drivability. 

"Although originally intended for aircraft and automobile use [it was the stock carb on the most famous Jaguar models among others], the SU carburetor has proven to be unmatched in performance when adapted for use on American V-twins such as Harley Knuckle, Pan and Shovelhead motorcycles.

SU Eliminator II carburetor rebuild kit

"The rebuild will be a complete teardown and deep cleaning using our ultrasonic cleaning technology. We will then reassemble your SU E2, using all new parts where needed, including new seals and gaskets. We will install a new jet needle, main jet and piston return spring of your choice, as well as a new needle and seat. We can even add an extended float bowl kit (by request) for carbs that will be used on strokers or big bore motors.

"Here is how it works: you send us your SU E2 free of gas and excess external grease/dirt via insured and prepaid UPS or USPS. It is extremely important to package the carburetor securely so that it will not incur damage in transit. Also, be sure to include in the package your complete contact information. It would be helpful to call us prior to start a work order.

"Once the rebuild is complete, APM will return the newly rebuilt carb to the address the customer specifies prepaid (applies only to continental U.S. addresses) and insured via UPS or USPS. The rebuild work will be covered by a 30-day limited warranty only against defects in parts or labor performed. Incorrect tuning by the customer is not covered by warranty."

It became a 'go-to' back-in-the-day because of the added potential it had over the entire rpm range where other carburetors failed to perform. The story of the SU is a part of V-twin industry lore - one that goes right back to 1908, when George Skinner got a patent for a carb with a 'collapsible chamber' and a 'fuel needle valve' and formed the "S.U. Company Ltd" in 1910 (S.U. being a contraction of 'Skinners Union').

Fast forward to 1970, and Mel Magnet (of Rivera Primo fame) reworked automobile SU carbs in his garage for Harley motorcycles. Mel's first SU customer was Bianchi Motors of San Francisco in 1972.

Many successes for the SU on Harleys followed - a highlight coming in 1978 when Dave Mackie's 1974 74" Shovel was the fastest stock production H-D with an SU carb.

Since then, much has changed in the performance aftermarket, but "one thing that hasn't changed," says Ben, "is the legendary status of the venerable SU and its 'old school' authenticity."