Rupp never used B&S engines. And good luck on finding a float type for a B&S. Unless you make a custom intake manifold and use a Tecumseh carb. If you want to make your life easy find a running h35, hs40, hs50 tecumseh. The h35 is what came in the bike with a diaphram carb and if you can't find a diaphram carb use a slanted intake with a float type carb on the tecumseh engine. And with that you can use the rupp gas tank. Hope that helps.