Hi I dont know how to tell if my bike is 50cc or 65cc. I believe its a 1965 model m aermacchi harley leggero. The frame and engine read 65m159?? Is this a m50 or m65 50cc or 65cc. Ive been to the Aermacchi pages but Im still a lil confused on this.It has the moped style gas tank(on the downtube),not the traditiiional style,if that helps. Can Someone help me please?Thanks