your clutch may need to ajusted .. i no mine did the same thing i would have the clutch all the way in and i would click it in first and it would die, but once i messed with it its fine now lol..
ya your clutch isnt disengaging. you need to adjust it to pull it "apart" more. simple way would be tighten the adjustment on the clutch lever on your handle bars. not to much or it will constantly slip because its not being engaged fully.