Hello, I'm new here, my name's Simon. I recently picked up a 2003 Z1K, and am going through it to make sure all the maintenance is up to date. It had the typical valve cover weep at the left front and I didn't know if the valves had been adjusted on schedule, so I thought I'd take the opportunity to check them since I had the VC off. anyway when I went to pick up the CV to put it back on I found this tiny O-ring setting on top of the right side reed valve. I suppose it could have fallen there during the disassemble or it could have been under the reed valve cover when I took them off. Does anyone have any Idea where it may have come from or goes? It measures about 6.2mm OD and 2.7mm ID.