Can you fit a 17" rear wheel from the newer injection model to the older 18"carb rear wheel model.
Purely for better selection of tyre choice.
Depending where you are in gods country you could have my wheel to see if it fits. My Sportie is just about to have the engine dropped out for some fettling. PM me if you want.
A few years back I had a Sport carb which came to me fitted with the Sporti 17" rear wheel. Looked as though it was made for it!!