Picture from www.vjmc.org Isn't that the Honda wing logo on the fuel tank ? Definately a Honda. looks like a Honda 175cc, circa 1971 Honda CB77 305 Superhawk, dirait-on... http://au.geocities.com/jimr_52/cb77motor.jpg pour voir le moteur de près... This is much earlier than 1971. The CB350 replaced the CB77 in 1968. With its instruments in the headlight it is quite early - maybe 1966. I will find out more.
Check out this link http://en.wikipedia.org/wiki/Honda_CB77 it even mentions Al Pacino in Serpico. Production dates 1961-7.