I know that the front of my Night Train gets very light if I crank the throttle hard in 4th gear. If I popped the clutch it would no doubt lift off.
I also know that my America will spin the rear wheel starting off before it will lift the front one when I'm sitting properly. I have a feeling that wind resistance would shift the balance enough to lift the front quite handily on the 3rd gear shift if I gave it a lot of throttle and let go the clutch.

Let's hope there's intelligent life somewhere in space 'cause it's buggar all down here. -- Monte Python