I'm probably nearing 60 hours or so of ride time on my 450. I thought the same thing cuz the manual says check it after break in. I checked them a couple nights ago and they were in spec. I didn't check them when I first got it but from the measurements I took, there hasn't been any kind of wear on them. Pahrump told me you could probably ride this thing for years and years and never have to adjust the valves but I would still check them. I read a post in some other forum that someone had checked theirs and they were way out of spec,(I think they hadn't even broken it in yet though. Anyways its extremly simple...........should only take you about 10 to 15 minutes to check them, hell if you haven't done the cam mod yet do both at the same time.