Below is a picture of the rear sprocket removed from the carrier and bike. You can see it is not like many other sprockets fitted to motorcycles. It took me a little while to source the correct sprockets for my bike and I believe part of that is the way the rear sprocket is different to the normal sprockets and probably that there are not many manufacturers out there that do their own way of holding the sprocket onto a carrier. Renthal are some of the makes I have come across. It does make it hard to source the sprockets as there are less making them for the Ducati 916 bp. These were replaced on the 26/10/2011.