Stay with the Monobloc, when properly cleaned, and set up, they are the best and simplest to maintain of any carby.. They are not only original to the bike, but they also look much better.. Once you understand the overlap in the different jettings, and get it right by doing plug chops, this carby is trouble free, and very easy and simple to work on. My 62 BSA Rocket Gold Star sat for seven years , because I was too lazy to take the head off and aneal the solid copper gasket (THE ONLY GSKT TO HAVE !!) , and re-torque the head back down. (Also some books say to torque alloy heads to 32 LBS). Do not do this, it distorts the head !!!! and causes leaks. I settled on 27 U. S. foot LBS, works great. Long story short, I never even took the float bowl cover off of the carb, just put fresh high test 92 octane in and started it up. That was 2006, still have not had the float bowl cover off, and it sat for 7 years with no gas in it, ( evaporated ) and have had no Monobloc carb problems at all. Just put gas in and went , been wenting for 6 years without ever opening carby up, so you see these are amazing carburetors when they are right. !!!! ( EVEN AFTER SITTING IN AN OUTDOOR SHED ALL OF THAT TIME !! )