Motorcycle won't run – GT125R Comet 2007

Hi, i have this problem with my hyosung that, if i travel at 100 km/h in about 5-10 minutes the bike starts dying, almost as it dosen’t have enough fuel. if i press in the clutch as this happens, the bike dies, and i have difficulties starting it up again. i think maybe it is the fuel pumps fault. i ride a Hyosung GT125R comet 2007 model, carburated, so the fuel pump goes on vacuum. does any one know if i it is the fuel pumps fault? or something else?  thanks for SERIOUS replies