I think I have reached a plateau with my C15 SS.
With the 18 tooth sprocket, it needs clutch slip at take-off, or in slow traffic.
Did a flat out speed run. 66 mph one way. 71 mph coming back.
With the previous low gearing, it was no faster.
At only about 5400 rpm, it is more pleasant and less strain on the engine.
At full speed on full throttle, when I ease the throttle back ,there is no loss of speed until nearly down to half throttle!
This suggests that the 1 1/16" carb is bigger than needed. It would be interesting to try a 7/8" if I had one.
8.5/1 comp ratio, scrambles cam, bigger inlet valve.
Mick