Thanks Bob, that took a lot of confusion out of it.I wrote about my experience on my ‘77 here. Lots of photos
When it does come time for new sprockets, these bikes benefit greatly from a small reduction in rear sprocket size, and by small I mean only one or two teeth. The stock rear sprocket had 34 teeth. If you have an 18" wheel, going down just one to a 33T is ideal. This is what the European models came with. If you have a 16" rear wheel, a 32T works well.
Just judging by your pics, I'd guess you have a 36-38T sprocket on there. Maybe even a 40TNice one 5T, did my first ride today and it became uncomfortable above 40mph.
I will check the sprockets tomorrow, and adjust accordingly with your recommendation.