How long do these engines last when given at least a fair amount of maintence, oil changes at a proportional interval to riding style? I have a 00 WR400 and change the oil frequently: after 3 days of hard riding or 500 mi. I have not adjusted the valves yet because I have not noticed any loss of power or heard any valvetrain noises from the top end. I ride this bike pretty hard and have never experianced the woes people have talked about. Hot starts after a get off, jetting and carb adjustments,accell pump timing ect.Am I setting myself up for a catastrophic failure.I bought my bike at NCY and they put my pipe on and did the jetting and carb tweaks.Is it my good fortune and maintenence or should I tip my hat to NCY for giving me a bike thats dialed in. What would be a good compression test result be and how many kicks does it take? The cam timing is stock WR so does changing it to YZ bring along a bunch of headaches. I am considering the YZ timing but have read that people switch it back to WR or put after market cams in. Does anyone have a trouble free engine and what if anything did you do to keep it that way?