Bonnie engine in oil-in-tube frame, better forks and finicky conical hub brake…new ones had variable build quality, if the tolerances went the right way then it wasn’t half bad; if they didn’t it fell apart rapidly. There are still lots of bikes with questionable mechanical integrity and it’s quite easy to buy a dog. Good ones are relatively smooth, oil tight and quiet. Later bikes had five speeds and disc brakes. Also single carb version.
1970-75 649cc (71x82mm) OHV twin 50hp, 120mph, 50mpg, 400lbs