Yamahas have these black steel spacers bolted to the swingarm that have a shorter axle slot than the swingarm does. They limit how far forward the wheel can go before the swingarm slot would. On my '05 WR250 and 450 I dremelled out the slots on the spacers so they match the slots in the swingarm. Now my wheel is farther forward than it could go before (the mark on the swingarm lines up with the last mark on the axle block) and there is plenty of tire and sprocket/chain guild clearence. I can't wait to try my more nimble setup! I can still add links and move the wheel back. Why does Yamaha sell the bikes with these limiters? It's like they designed the axle slots in the swingarm and then changed their minds about how much of that adjustment range should be used. The thing is, they've been coming like this for at least 4 years.