It might be good measure to order a new gasket for the fuel sensor,that could be the problem.take the tank off and look underneath,could be pin hole in tank.hopefully not.

 

Oh my god, I laughed so hard. I saw this thread and began reading... all the very sharp warnings and direction to stop immediately and rebuild the petcock, and the OP appeared to ignore all that. Sorry, maybe it was those beers at lunch.

I'm easily amused.

 

holy ****!!! i just found a fairly large o ring next to my old sensor. i bet this is the flipping problem. the sensor i put on the bike i did not replace the o ring or put one on at all. i'm an idiot.

 

That would do it! Which may explain why when you put gas in that it leaked out (probably to the level of the sensor) and then stopped.... That must have been a lot of gas coming out. I'd imagine at a station you could get 6 or 7 gallons in the tank lol