The bike in question is a 1992 7 speed Cannondale R600. In the last month I have crashed it and added a new chain. Two days after adding a new chain I noticed that the two smallest cogs are "skipping," either in the small or big chain ring. By skipping I mean that the chain normally wraps around the rear cog and then consistently every once in a while (depending on how fast I am pedaling) the chain bumps up and then goes down again. I took a video and posted it to youtube, hopefully it embeds properly. Any thoughts? I should also add that the I made my chain a half link shorter (or is that one link?) because my chain tool was being a jerk. One more think, it is most likely not a derailleur issue, I spent a good hour adjusting it and it didn't do anything to the problem. All the other gears are synced up just fine.