OK! Well I yanked off 1/2 the discs from the supertrapp. Also backed the fuel-air mixture screw out 2,1/2 turns (from 2). Here you see two vids below, the cold start just to prove it starts after a day of rest, and then a few minutes later after it's had some time to warm up, maybe 2 minutes, I switch off the choke and directly after a backfire (cough) with a puff of smoke. Curiously it won't restart, even with the choke on...like i startled it or something...motorcycle foreplay is a dark art when dealing with large bore thumpers: such sensitive beasts.
Now, IF there was an air leak, I would imagine that the idle would be surging much more than it is, even with the starter enrichener engaged, right?
Maybe something else is awry here.
Here you see it die and me go at it with the kickstart. Yes, I strap those lineman's boots on every time. Doing it with flip-flops would ravage even the heartiest Barbarian size 13.