After hearing about o-ring chains wearing through the engine cases around the counter shaft sprocket, I thought I had better check mine. Not too much wear but I modified the CS sprocket anyway to move it 0.060" outwards. I found a 316SS washer 0.060" thick (1.25" OD) and drilled the hole to 1". Then got a friend to cut a 0.060 pocket in the sprocket face. The washer goes on the back of the sprocket, spacing it out, and the pocket allows you to still get the retaining circlip on. An easy mod and fits nice. Time will tell if helps much. Here is a pic. Cam.
ps. the renthall CS sprocket was extremely hard (which is good).