Bought an '03 WR450 new 9 years ago. Aside from the free mods, rejetting, starter gear fix, and decompression plug, left the motor stock and just did normal maintenance. This bike has been flogged for 7400 miles off-road and has been absolutely bullet proof. I have smashed the left radiator (still didn't leak), bent the choke knob from impact (still ran, but with vacuum leak), cracked the clutch cover (slight oil weeping, but rideable), dinged up the pipe, ripped off shrouds, flattened a foot peg, and bent the shift shaft 20 degrees - all on different occasions - and still rode out every time without fail. The only maintenance issues that were not caused by yours truly were a leaking water pump seal and a stuck carb float valve. And actually, the float valve was my fault for being lazy and not draining the float bowl between rides. Just checked the valves the other day and they are still in spec, have yet to be adjusted since new. Had one intake go from .005" to .004"+ clearance, the others have not changed at all in 7400 miles. Unbelievable.