I have been given an XTM 200 with a ZongShen 200 engine, I have ridden it a few times when my mate owned it and have noticed that when held on limit in fifth gear for any more then a couple seconds it seems to die out and splutter but then you release the trottle and blip it a couple times and its good to go again. Does anyone know what this may be, im thinking the main jet may be too small or even the carburettor