did you bench sync the carbs before you put them on?
the manual explains how to adjust the throttle plates before you install on bike.

 

Possible Vacuum hose disconnected at the number 2 Carb manifold vacuum hose for Synchronizing the carb.

 

There arnt vaccum hoses. They are screws that you have to remove and replace with fittings to put the hoses onto.

 

Mine was doing this and was lean on the crossover from pilot to main jet. Took a lot of time tuning it and when the weather warmed up it was off again. Just a little stumble. But its a rocket it should be running 4k rpm or better unless youre lugging it.