G'day all,
here is a mod most of us can use. When I raced I would need different gearing for different tracks and '56/'57 rear sprockets are hard to get and expensive.
Take your old sprocket and mark a 160mm circle now mark 6 equidistance points on that circle and drill 1/4".
Now take a blank sprocket and do same. Bore new out to line and turn off the old to line. Use 6 X 1/4" HT bolts to hold together, sort of like scotch keys, the same as the break discs on new bikes.
Cheers
