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How to Fix a Motorcycle Carburetor


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Air Adjusting Screw
How to Fix a Motorcycle Carburetor

Note the position of the air adjusting screw before removal.

Photo copyright John H. Glimmerveen

One other item to be removed from the carburetor body is the air or fuel adjusting screw. To identify which type is fitted to a particular carburetor, you can examine the screw's relative location to the slide. If the screw is on the air filter side of the slide, it is an air adjusting screw; conversely, if it is fitted to the engine side, it is a fuel adjusting screw.

Observe the Screw Position.

This tapered screw affects the mixture strength (rich or lean)  during the first third of the throttle opening and works in conjunction with the primary jet. Before removal, you must check the screw's position. The screw will be set at a number of turns from fully closed (turned all the way in: clockwise), and should be put back to this position upon reassembly.


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