Please help Identify Mystery Part

[Blazer]

While rebuilding the top end of my 82' 110, I found this part on the floor (even though I thought I had carefully organized the parts into separate plastic bags). I have been looking through all sorts of diagrams and cannot figure out where this goes. The part was a bit oily when I found it, and has a rubber oring that fits inside. I suspect it is an oil seal for the CDI, but I can't find out where it looks like it should fit. If you can Identify this, please let me know!

http://i148.photobucket.com/albums/s10/Bullet0405/Mystery%20part/th_102_1556.jpg (http://s148.photobucket.com/albums/s10/Bullet0405/Mystery%20part/?action=view&current=102_1556.jpg)
http://i148.photobucket.com/albums/s10/Bullet0405/Mystery%20part/th_102_1557.jpg (http://s148.photobucket.com/albums/s10/Bullet0405/Mystery%20part/?action=view&current=102_1557.jpg)

[atc500x]

99.99% sure it's a valve seal
#7 and #12

[Blazer]

That was it! Thank you for your help. I'm glad I found this out before reinstalling the cylinder and head. Getting the valve retaining clips in was a PITA!

[oscarmayer]

lol I was just going to say it's a valve stem seal gone bad.