With the rear wheel out of the way, it’s a good time to clean up the swingarm.
I have no intent on reusing the original chain, so out came the angle grinder with cutting wheel which made quick work of taking the chain off.
The original 16-tooth sprocket on the left and the new 15-tooth sprocket on the right. You can see the new sprocket has some mass removed as it lacks some dampening looking material. It probably doesn’t contribute to a great reduction in inertia in the grand scheme of things, but every little bit helps, especially on a sportbike engine where many parts are already mass optimized.
This is a better view of the lack of material of the new sprocket versus the original.
There’s not much mass reduction opportunity on the rear sprocket.
The new rear sprocket is a bit thinner than the original to match the new 520 size chain versus the old 525 chain.