I have to buy a carburetor for my BSA B50 for the new build. For the last two years I used a 40mm Amal mark II, which is similar in construction to the Mikuni Round Slide carbs, with 36mm port size. My new cylinder head will have a larger intake valve (1-7/8" vs.1-25/32") and larger port size (40mm). My engine builder recommends the 44mm Mikuni round slide. I was thinking that a 42mm flat slide might be a better choice to make sure the fuel(gas) stays in suspension with the relatively small port size.
Can anybody shed some more light on this choice?
Tom