Get up to speed in second gear around 7k RPM's (about 80 MPH) and just crack the throttle open and it should come right up!
If you are a little on the heavy side(200+), then punch the gas in second until around 8k RPM's and then slam the gas off quick! Once the suspension springs forward and unloads the rear end squat, Nail the gas again and it should power right up.
Always be ready for it to come up quick and cover the back break if you feel like it's to high. Just take it easy a few times because the speeds get pretty quick when you do the second gear 80+ MPH wheelies! Once you get it up and balance then just click it into 3rd, 4th, and so on until you can cruise with the wheel in the sky!
Have fun and be safe!
P.S. You shouldn't need to pop the clutch on the BUSA to wheelie, it's got enough power to come up on it's own.