Okay, so maybe Gorrs arcticle got to me a little bit, so today I tore down the top end on my 2002 YZ426. I tore it down only to find the piston and rings still looked like new, the valves where still in spec too. The cylinder still has the cross hatch marks in it too. This bike does not have an hour meter on it, but I bought it new, rode the chit out of it, and changed oil every other ride, and I think it would've lasted 2 more years at least on this top end. So I guess the only good thing that will happen now is a high compression piston and a 450 cam. How many of you recommend a high compression piston over the stocker? Is it a big difference in boost?