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S&S Shorty Carburetor Adjustments

Gettin Back To Baseline

Photos and text by Howard Kelly
6/10/2010 9:37:41 PM

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Editor’s Note: We are going to work with S&S, Baker, BDL, Compu-Fire and other Bikernet Sponsors, on their most asked tech questions. We’ll try to deliver the info you need access to. The following came from Howard Kelly, the former editor of HOT BIKE, and now an S&S tech editor.

“We take tech calls all day long here,” Howard said. “Most people have monkeyed with their carb so much they lose the baseline. Before we can do anything else, we have to get them back to a starting point so they can tune the carb to their bike. These 10 simple steps make tuning an S&S Super E or G a breeze--on the road or in the garage.”


1-Verify carburetor is set to stock settings:
A. Idle Mixture Screw, 1 1/4 turns from lightly seated
B. Idle Speed Screw, ½ turn clockwise from engagement point
C. Accelerator Adjustment Screw, 2 turns counterclockwise from seated

1. Start bike, bring to operating temperature. Close enrichener as quickly as possible.

2. Set Idle Speed Adjusting Screw, clockwise to increase rpm, counter-clockwise to decrease rpm

3. Adjust air/fuel mixture by turning Idle Mixture Screw slowly clockwise until the engine runs poorly. Slowly turn the screw counter-clockwise until it runs smoothly—if you go too far the engine will start to stumble.

4. With engine idling, turn Accelerator Adjustment Screw clockwise until it lightly seats. Snap throttle open—engine should stumble. Turn screw counter-clockwise ¼ or ½ of a turn at a time, until engine responds to throttle twist with smooth, quick response.

5. Ride motorcycle in various RPM ranges, and then try to maintain a consistent 40- to 50-mph. If the engine is popping or sneezing in the air cleaner it can indicate a lean condition. If you notice stumbling or sputtering it can indicate a rich condition

6. Replace Intermediate Jet as necessary—smaller is leaner, larger is richer. Adjust Idle Mixture Screw and Idle Speed Screw as required.

7.To test the Main Jet, do a high gear roll-on from 50-mph to 70-mph. If the engine back fires or breaks up in the carb, increase the Main Jet size .004”. If the engine is flat or will not accelerate, decrease the Main Jet by .004”.

8. After changing the jets, test ride the motorcycle. Continue re-jetting and adjustmenting until optimum performance is achieved.

Note: Drag or straight pipes can prevent you from obtaining optimum carburetor performance.


Howard Kelly
S&S Cycle Inc.
235 Causeway Blvd.
La Crosse WI 54650
(608) 627-0284

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Reader Comments

Comprehensive and well-written, pretty much covers everything, but could have touched on air leaks, which must be addressed if carb is going to function properly at all.

Molalla, OR
Saturday, January 28, 2023
Editor Response You're right. Feel free to share a tech tip, and I will share it with our readers.
i live in Colorado about 65 north of Denver I have changed the intermediate jet to a .295 and the main jet to a 70. It will backfire though the carb once in a while. Could you tell me what you think do I need to go up with the main jet of down. We are over a mile high here I can't seem to get it to run right.

Robert Onorato Onorato
Milliken, CO
Saturday, December 1, 2018
Editor Response I'll get you some help, quick.
Can someone tell me a good start on jet size for a '05 Dyna FXD with Vance and Hines st8 shots with super E Shorty 88-inch Twin Cam ???

Travis cooke
Lennon, MI
Tuesday, July 24, 2018
Editor Response I sent you email to David Zemla at S&S. I'm sure he helped. Let me know if you need anything else. Did you buy a Jet kit?
Nice to learn

Aasmund Gresseth
Hegra, Stjørdal, Norway
Tuesday, July 10, 2018
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