So having tried 3 carburetors on my 490 speedster so far I think (for now) I have a good 1. Its a updraft Tillison JR1 that has a accelerater pump. What carbs is everybody running? Updraft, downdraft, sidedraft? Rooster
I think that the Filling Station sells a modern replacement for the updraft carburetors. As long as the engine displacement is close to the range of the carburetor it should be an option.
Original carburetors are available but can be pricey.