I was getting the bike ready for winter storage today. I pulled the sparking plugs and put fogging oil in the cylinders. put dielectric grease on the plug caps and reinstalled the plugs torqueing them to 13 foot pounds. I was working on the right bank on the middle plug when I found I couldn't get the socket to seat on the plug. I looked inside the socket and found this rubber grommet in there. It looks like it might have come out of the plug cap of the rearmost spark plug since I had just been working there but it seems too big to go into that cap and in looking at the rest of the plug caps I don't seem to see this thing in the others. Does it somehow have to get squeezed into the plug cap? It seems like it would since it has some ribbing inside it which would seem to suggest it fit over the spark plug. Anyone seen this thing before?