My son has a '76 CB500. He put on a new chain and sprocket and now says the chain is wearing down the sprocket at an alarming rate (he's noticing metal shavings around the sprocket). I had no anwers for him but I told him I would ask here as there are some mechanical geniuses lurking that may be able to help
. My advice was to find a bike with shaft drive (a lot of help I am!).