when i first got my gst it wouldnt even run a whole tank without seriosly overheating so pinned it down to a crack in the carb so cen sent me a new 1 it was a bit better but not good enough for my liking so i had a carb of an lrp 30 lying around so i modified it to fit in and it would run tank after tank until the hump pack would go flat with only occasionally cutting out coming off the throttle being flat out so i fitted a fastrax primer/filter bubble and i reckon its cured now, goes like a total dream now. So if ur willing to put the work in its really pretty good and you get the satisfaction of sorting it too