Seems weird that i drove 3 times and it was fine but once i really get on it and take it over 10k it just starts sputtering out when its coming back down.
From most of your descriptions so far, this sound like a fuel supply issue, and the comments from the rest are good places to start...
a) Make sure the petcock is flowing fuel strongly. To test the vacuum on the petcock, you can usually suck on the vacuum hose with the petcock on ON.
b) It's harder to test the tank venting...but you can ride with the tank cap partially open to help identify if this is the problem.
c) Assuming you have fuel flowing strongly from the petcock, then make sure you have fuel flowing from the carb drains. If not, you will have to dismantle the carbs and find out what is blocking the inlets. If you have fuel flowing from some, and not others, then likely there is something plugging or hanging up in the individual carb Float Needle Valve. If you have no fuel flowing from all carbs, then start looking the the fuel line or fuel rail that feeds all carbs.
d) Also, make sure you drain the tank to ensure no water, and start with fresh fuel.
Let us know how you make out.