Hi all I just went through the work of rebuilding these twin carbs, these have the floats in the bottom, and the power valves on the sides..... Still runs rich, so i reversed the rubber gasket on the power valve, lowered the needle valve all the way down. Runs better but needs plenty of choke when cold. No black smoke like before, i have since read that these carbs were crap and recomended using the previous years carbs. Anyone had the same problem.