The stock Mikuni carb is a POS, and has a rat's nest of hoses associated with it. All the more reason to junk it and replace it with a Weber 32/36. IIRC, the only line you have to hook up is the vacuum advance one coming off the distributor, and of course a fuel line. All the other ones you can just leave unplugged, but you'll have to plug the end of the water hose that goes into the base of the stock Mikuni carb.

Do a search on here, and there's quite a few posts about replacing the stock Mikuni with a Weber. This could also be part of your lack of acceleration problem. When I first got my Monty, it could barely get out of its own way. Found out that the secondaries were shot, so I was basically running on a 1-barrel. The Weber GREATLY improved the daily driveability, once I got the fuel/air and idle settings more or less dialed in.