Is the carb set up one you put together or a trinity. Not that it matters. Just trying to gather you info to help.
What size carb is it? I have had a 38mm which works fine, I have had 36mm carb which works fine and a 35mm which aslo worked fine as well.
How clean was the carb.
What jetting do you have.
Have the jugs been ported?
Have the jugs been bored?
What kind of air filter are you running?
Open air box or closed?
Has the head been milled or is it stock?
What grade of gas are you running?
Again, not that it matters, but it might?
Don