How to Set the Mikuni Carburetor Float Levels

by Lisa Wampler

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Mikuni carburetors, commonly installed on motorcycles ranging from small single cylinder dirt bikes to V-Twin motorcycles, have a plastic float to regulate fuel consumption. The float in the Mikuni carburetor sets the height of gasoline that rests inside the bowel. If you set the float too high, you risk overflowing gasoline from the carburetor and if you have it set too low, you risk running out of gas when you have your motorcycle at higher throttle positions. Mikuni has specific measurements for the setting the float levels.

Step 1

Remove the four screws that hold the float bowel onto the bottom of the carburetor. Pull the float bowl and float bowl gasket off the carburetor. Use a Phillips screwdriver to remove the float bowel screws.

Step 2

Place the carburetor upside down and let the float rest against the float needle. Do not touch the float at this time.

Step 3

Measure the distance between the gasket surface located on the bottom of the carburetor to the edge of the float. On a 24 mm Mikuni card, the distance between the gasket surface and the float should be 1 inch. On a 20 mm Mikuni carburetor it should be 7/8-inch. Use a precision ruler for this.

Step 4

Bend the metal tab on the float that rests against the float needle. Bend it towards the float needle if the measurement is shallow and away from the needle if the measurement is too much. Use you finger to bend the tab. If you cant bend it with our fingers, use a pair of needle-nose pliers. Make very small adjustments to the metal tab and then recheck the measurement.

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