ok, I just got my first moped earlier today. it's a vespa grande. They guy i bought it from said it had been sitting around for some time (like 20 years) so the gas and old were messing up the tank. I got home and was all excited to ride it, but half way through my journey the engine began to shut off and on. I pulled the throttle and it finally just shut off completely. I think it has to do with the old gas. I refilled it with gasoline and oil, i also added a little engine cleaning fluid. I don't know to much about mopeds and was wandering what might be the cause of this. ALSO! how do i make it go faster?? it goes about 15 now. and in dallas thats ganna get me killed! so any suggestions? thanks