jim get someone with a lathe or mill to cut the centre out of yours and bore the centre out of a new 13t sprocket and make it a interference fit so u can press it over old centre makeing sure u keep the same original centreline [so the chain lines up] then get some one to tig weld it up then linish off and sent off to zinc platers [finished].ps if u dont have and old tapered keyway sprocket then give me a ring over the weekend cheers chris
