ridnwarrior- The kink in the vent hose is a very common problem. Just because it is not your answer doesn't mean it isn't right. Just at idle or putting around you may not notice a kink in the hose but after you start getting on it(warmed up) you will notice the motor starving.

On the other hand I have never seen a fuel line so long on a blaster it was even close to anything hot. Hope he finds his problem because I know it can be frustrating.

 

Pull the spark plug immediately after it stalls. Is it black, oily, or does it have a bridged gap? Sounds too rich. If it only does this on WOT, then you have a too rich condition on the main jet circuit. Jet it down, and see if it makes a difference. Your problem is definately carburetion.