How to Properly Set Float Height
To set the float height, it is first necessary to determine the current height. This can be done by measuring the height of the float above the carburetors gasket face. First remove the float bowl from the carburetor body. With the float bowl removed, tip the carb, in the same position it takes while fitted to the bike. Attach a clean tube to the fuel inlet. Now blow gently into the tubing, while lifting the floats slowly until the air flow stops. This is the measuring point for the specified float height. You are going to measure the distance between the float chamber face to the top of the float at the point the float closes the float valve.
The distance to measure is available in most service manuals. PLEASE be sure to triple check any information found on a forum or elsewhere on the interwebs!
The distance to measure is typically measured from the float chamber face – or gasket surface – to the highest point of the floats. If the floats are not at the proper height, most floats have a smakll tang that contacts the float needle which can be bent gently to adjust. Bend the tang toward the needle valve for less fuel to be allowed in (the bike will run leaner) or, away from the valve to increase the fuel level (the bike will run richer).