I've been looking into installing a pair of Mikuni HSR42 carbs on my B20, using a conversion kit from John Parker at VPD. I haven't found any detailed threads about this, so I'm thinking of documenting the process and results here (possibly in a new thread depending on how long it takes to get the parts).

I have found two used HSR's from upgraded Harley kits, and I'm going to use parts from VPD to convert them to B20 linkage. I'm keeping a tally of all my costs so I can list them here (a total conversion kit from VPD pushes $950 with filters, I'm shooting for a lot less than that).

The good news for Brickboard is that I'll be selling my SU HS6 carburetor setup once this project is completed. I rebuilt the carbs a couple years ago after soaking the appropriate parts in carbs cleaner and cleaning them out (it ran before the rebuild but it was pretty rough). They have good throttle shafts. I've been working on getting the car road legal since then so it hasn't been on the road much. Luckily I live on a dirt road out of town so I can take it out every so often, just to run it through the gears and keep it from sitting too much.

If anyone is interested in a Mikuni conversion thread or in my SU's, reply here or PM me. If no one cares about Mikuni's then I probably won't bother.