After working on my '06 450 this weekend I pulled it off the stand and noticed a "clunk" when I set the rear wheel on the ground. I put it back on the stand and after checking bolts and the like, noticed that there is a little play in the swingarm. When I pull up on the swingarm while leaning over the seat it moves a bit. I've checked all the bolts on the swingarm / sub-frame / shock mounts and they are all in spec. There is no play laterally either. Any ideas on what I'm missing?