flooding the cylinders...

k...so here's my newest problem, finally put the tank on today and it started hydro-locking the cylinders......is this a petcock problem or a carb? i took the petcock off and checked the diaphrams and it looked fine to me.....
i can run the bike off of a makeshift fuel supply but when i hook the tank up it locks it up? wtf? any help is greatly appreciated!!!!! thanks guys/gals!!!:unsure:

 

Sounds like you have one or more stuck floats in the carbs.

 

but i just rebuilt all of the carbs....jets are clean, needle and seat moves freely, and the floats are clean ....everything is copasetic.....heeeellllpppp! this sucks, like i said, i can run it fine off of a makeshift tank, could this be a vacuum problem? could that cause it? or should i really check my carbs again...cuz i really dont want to take them off again.....we are not friends, lol