From the vid it sounds like the bike is turning over fine. Wet plug = fuel getting through. From your description it sounds like the coil is going down to ground. Coil and HT lead/Plug cap is where I would be heading I think. CDI? maybe....but could also be the sender which sends the signal to the CDI when the crank turns. As I said to someone else on here....start with the simple things and then work up from there. Plug first, Coil/HT Lead/Plug Cap, then CDI and sender. Also check the compression. If the compression is down you'll have trouble getting it to fire up. If the guys could only get it to run on higher octane fuel it may be that the compression is low.