The purpose of the float circuit is to maintain an adequate supply of fuel at the proper level in the bowls for use by the low speed, high speed, pump and choke circuits. Primary and secondary bowls are separated by a partition. The fuel line connections is above the secondary needle and seat. Fuel is supplied to the primary needle and seat through the passage in the bowl cover.
Setting the floats to specifications assures an adequate supply of fuel in the bowls for all operating conditions. Float adjustments must be made vertically (specified distance between bowl cover and bottom of floats) and laterally (sides of floats should clear the arms of gauge). Having the float bowl gasket on or off will be dictated by the carburetor kit instructions. Correct lateral adjustment is important. If the floats are misaligned, they may bind or drag against the inner walls of the bowl. Adjust by bending the float arms.
To avoid unnecessary bending, both floats should be reinstalled in their original positions and then adjusted.
The bowls are vented to the inside of the air horn and on certain models also to the atmosphere. Bowl vents are calibrated to provide proper air pressure above the fuel at all times. To assure a positive seal, always use a new bowl gasket when reassembling. An air leak at this point can result in poor mileage.
A connecting passage along the outside of the body effects a balance of the fuel levels and air pressures between the bowls.