Finally the penny drops. I thought those carbs were keihins now you mention it, they are the Chinese copy that say Mikuni on the outside and are Keihin designs. That way Neither Mikuni nor Keihin can chase them for copying. Clever people. IIRC they are 30mm at the outlet so they are not as large as that at the slide or venturi, so they shouldn't be too large after all and may turn out to be a good choice for midrange power out of corners.
