I thought I posted this once but don't find it. Anyway, what's the difference between the late 60's and the early 70's? The two-speed belt drive to the transmission had been dropped by the time of the late 60's and the early 70's had just one pedal, as did the 60's. So, other than maybe the seat and the one more advertised engine hp of the 70, what's the difference between a late 60 and an early 70??