Everyone told me that the agility was diff from a gy6, but I just had my crank replaced and all the seals , gaskets, rings, and oil pump. The guy that done it says the engine is identical. I am having a vibration that comes and goes but my Tranny , (final Drive) isn't making any noise. I have notice my belt is looking a little ruff. its almost a fluttering vibration. I hope my tranny doesn't have a bad bearing, but you would think itd make noise. What do you guys think?