I was talking to some guys at a cycle shop today and they specialize in KTM and any suspension, any way some guys that know a heck of a lot more than I do about bikes, I think. They said I am waisting my money on synthetic oil as long as I change it every other ride which I do along with my air filter. Ok I belive him and I will probably stop buying synthetic but he said he runs Rotella 15w40??? This oil is most popularly used in diesel engines, has anyone ever heard of this.