I'm riding a 2002 WR-250F, which is my second WR-250F (foolishly sold my 2009 model). With that 2009 model and with this 2002 model, I did all of the "free mods" and other uncorking mods that everyone else does, but always kept the exhaust cam timing in the original WR position. That is: Compared to a 2002 YZ-250F, my 2002 WR-250F comes with the exhaust camshaft advanced one tooth. This means the exhaust valve opens and closes sooner compared to the YZ, resulting in less valve overlap, and, less power. Or, so I had always read. I always wondered if the smooth and very controllable power (which was also hard to stall in very slow going unless I simply made a mistake) of the WR would be traded away for more maximum power at higher revs with the YZ cam timing. This week, I finally decided to retard the exhaust cam to YZ spec. and see what I got. This morning before leaving for work, I took the bike for it's maiden voyage in this condition for a very brief 2-mile putt down the street to make sure all was well after putting it back together, as well to get a small sample of the results. So far, the bike undoubtedly feels more peppy from just above the basement revs on up, as well as pulling through the revs with more force. The low-end, as far as I can tell so far, is either unchanged or changed to a small enough degree that I can't tell. Yet. Basically, it feels as if it just received a shot of adrenaline which is quite noticeable. In all of the posts I've read over the years, I can't recall anybody giving some kind of a detailed back-to-back comparison of WR cam timing vs. YZ cam timing, with the usual opinion being, "There's more power everywhere...", and not much else. I've even asked others, who really like the YZ cam timing and always recommend it, what the comparison felt like, only to be told they'd never ridden the bike with the stock WR cam timing. So, after this weekend's Sunday 43-mile trail ride (the real test for me), I'll write down in detail what the difference feels and performs like, and any pluses or minuses along the way.