got rear sprockets off rob at racing lines, this little beauty is a renthal aluminium one, weighs ounces, when we measured the chain run we found out we were 2mm off-centre so had to make new spacer for offside and mill down the nearside one to bring the wheel into line, good news was that reversing the sprocket gave perfect chain alignment with the front sprocket, bad news was that we had to alter the rear caliper mounting bracket because the pads were binding on the disc, hate those chain adjusters, got to sort them out, fucking horrible, looking at the dangerous sport classic ducati i'm thinking along copying those, lot's of work mind but they have to be better than these.