I run 32mm VM Mikuni carbs on my CB 450 Race bike, spent lots of time trying to figure out the jetting and now have the bike running well. I have a smooth idle, no serious dead spots and great top-end! I am using the stock jet needle and needle jet that comes supplied with a new VM 32mm (you can look it up on Sudco or Pro Flows sites) and I believe I am in the third (middle grove with the clip). I am currently running 160 mains and 37.5 pilots. I started around 180s and kept going up. At one time I was up to 220 mains and the bike was terrible and getting worse. I finally realized I was going in the wrong direction. I may even try even smaller mains say 150 or 145. I must mention that I have made many other mods to the engine that may not relate to what you are doing. I have a +3mm piston kit (483 CC by my math) did some mild porting, added about a 40mm aluminum manifold extension, machined in two more spark-plugs and machined the intake cam to accept an exhaust cam sprocket so I could adjust the cam timing. The bike rips! But remember, the right way to go with jetting may be opposite of what seems logical. That is, increasing the displacement while using the same carb may mean you have to decrease the mains instead of increase them due to greater differentials in pressures and greater velocities in the venturi. Maybe the stock 444ccs would run better with 175 mains for example. Who knows!! Good luck with your project, and, by the way, I put VM22s on my 160 and not having the best luck getting them to run right, any Ideas?