Gents,
I set out to do what I thought would be an easy change of engine sprockets, but it is turning into a chain adjustment mystery.
Edit: I've pulled the question because I think I already know the answer. I'll be back.
All this just to go from 21 to 22 teeth, which, I am thinking, will let me cruise comfortably at 40 MPH in 3rd (on SC gearbox) and move the 4th-gear sweet spot to around 53 MPH.
Thanks for your help.
Richard L.