i'm almost finished with my sachs + puegot simonini build, this weekend will be the break-in/tuning at whiskey biz, i'll be sure to post results.
i'm running a dellorto SHA which fit right on my C motor, i dunno about fitting it on a sparta frame or an A engine. The square bings can be drilled out to at least 14 mm, which should be plenty for 40 mph with a pipe.