I had the same problem with my brand new 2007 TBA, It turned out to be the tip over valve was stuck. It is a small check valve that mounts in line in your gas tank vent hose , the valve itself is mounted directly behind your carburetors. the valve gets stuck shut and wont allow your gas tank to vent properly creating a vacuum in your tank. If you go to pages 25 and 21 in this forum ,you can read my account and member responses. My bike died on me repeatedly just like yours. It's an easy fix and a common problem, good luck.
