I just bought a very slightly used 2006 YZ450SE. It looks like it was looped out once by the previous owner and he called it quits. Anyway on my 3rd lap around my local track after setting the sag the lower spring guide failed on a small 20ft table top. The upper steel plate that the spring rests on it still somewhat intact but the lower aluminum guide is MIA. I guess it broke in half and is somewhere on the track. Luckily other than some tire marks on the fender and the inside of the exhaust can there was no significant damage. The fix is cheap, about $25 for the two lower spring guides from the local dealer. I'm just wondering if anyone else has had similar failures? It seems really unusual. I'm just glad it happened on a small jump rather than on a large rhythm section or something.