Question: How To Adjust A Mikuni Carburetor On A Harley Davidson?

Where is the idle screw on a Mikuni carburetor?

The air screw can be located either near the back side of the carburetor or near the front of the carburetor. If the screw is located near the back, it regulates how much air enters the circuit. If the screw is turned in, it reduces the amount of air and richens the mixture.

How does a Mikuni carburetor work?

The starting system works by opening a passage that allow more fuel to pass through a different set of jets making the mixture richer. The starting system (choke) only works if the throttle is kept closed, if you give the carburetor any throttle with the starting system on it won’t work.

How do you adjust air fuel mixture screws?

Turn the screw clockwise until the engine starts to sound rough.

  1. Tightening the screw weakens the air and fuel mixture and decreases the amount of fuel flowing to the engine.
  2. Tightening the screw is also called making the fuel mixture leaner, which lowers the RPMs at which the engine idles.

What happens if main jet is too big?

For example, using too large of a main jet will cause more fuel to enter the combustion chamber than it can efficiently burn. This will result in a “sputter” at full throttle. It could best be described as a rapid misfire.

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How do you adjust a running rich carburetor?

Regardless of whether or not the engine is running too rich or too lean, bring it down to a very lean mixture by turning both screws a quarter-turn at a time, counter-clockwise, then slowly bringing them back up to an equal and smooth mixture.

What does raising the needle jet do?

Raising the needle by lowering the chip position at the top of the needle will richen the mixture. Lowering the needle will lean the mixture. WIDE OPEN THROTTLE: Changing the MAIN JET affects this range. Select the size which offers the best wide open throttle.

Is a Mikuni carb good?

5.0 out of 5 stars Good carb, all in all. The Mikuni carb is a great carb. The company that should those one to me was great.

How do I know what size Mikuni carb I have?

Re: Identifying Mikuni carb size? Measure the inside diameter of the carb on the engine side. That will give you the size. Most of the internals will be marked as to what size they are and a lot of them can be ordered separately as needed.

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