G'day! 
Desperately need help with outofbox 42 Mikuni. If you can recommend someone, please send me a PM.
Cheers!
 

Just can't tune up new carby.. Bike fires up and running but as soon as I let the throttle go motor cuts off... 

Well, I installed Mikuni on Buell XB 1200 engine (converted it to carby). Now it runs with ignition and carb for HD Sporty. Got all new gaskets on intake manifold. Seems all good and I've ridden the bugger a few times around the block.. but I just can't idle the carb up for some reason....
that's what I'm talking about

 vacuum leak will often give same problem check seal behind carb and hoses

hell yeah! I got it! replaced round seal between carb and manifold... thanks a lot for your help!

Sometimes Dazza you just gotta check twice