rmyers I change my own all the time but never noticed an extra o-ring in the box. About how big is the o-ring. It might be that they finally decided we need one on the drain plug. I use liquid Teflon tape on the drain plug as they all seem to weep.
It is about 3/8" in diameter, too small to fit around the drain plug. In fact it is about the same diameter as the inside of the drain plug. I just left it off, as the service manual doesn't mention anything about it.
I would have thought it to be an oversight except for the fact that the parts guy specifically mentioned the o-ring being in the box. I could not find it used anywhere, so I put it aside. Took the bike out for a nice ride yesterday, and all is well. I will try and finish the 1000 mile service this weekend.
It could still be the plug O ring. I have seen O rings that were much smaller than the item they were supposed to be on. For example...... On a Bravo 1 outdrive (boat talk for a sec) there are two O rings on the shaft that goes back into the boat (driveshaft), Both of them do not look like the belong on that shaft due to there much smaller diamater.
Try it on the plug......just strech it around it.........it will probablly work!