hi there i have an aerox 50 and it jusr wont run properly its getting through a spark plug every 2-3 weeks and keeps breaking down on me it has had practically a full engine re-build and it still isn't running properly =/ i have been told a few things that it may be such as that the carb is set up wrong, the jet has worn out (so i've ordered a new one from my local yamaha specialist) or that the carb has done its time and now needs changing but i dont know what size carb it has. So does anybody have any usggestions on what the problems and solutions may be?