I rode with an (unhappy) YZ250FX owner on the weekend. In the snow no less !
We traded bikes for about half an hour. He used to own a carbureted WR450F, pretty much stock.
He doesn't like how "lurchy" his YZ250FX is. The throttle has an on/off feel to it that makes the engine either want to pull hard or decelerate. This bugs him. He has put a different throttle cam in it. I noticed it when I rode it. I'm used to riding my WR450F, so I could more or less negate it with good throttle control, but you could tell it was there.
Another rider had the same comment about the lurchiness of the YZ250FX. When I said is didn't really bother me, both of them looked at me like I was a bit off. They both like the soft bottom end of a 2 stroke. I'm used to riding my WR, where a wrong flick of the throttle in slippery conditions can get you into trouble.
I was pretty impressed with the YZ250FX. On the scale it probably weighs the same or more than my (lightened) WR, but it was quite a bit more agile. I liked it much better than a 300cc 2 stroke. More stable and planted. Less twitchy. I think its the best feeling single track bike I have ever been on, chassis wise. Better even than a Sherco 300, for me, anyway.
Suspension wise, I thought the fork was awesome and the rear suspension was too stiff on high speed damping. Easily fixed, especially since I revalved my own WR shock.
Power wise, I was surprised at how burly the bottom end was, for a 250 anyway. Being we were riding up in the mountains in pretty slippery conditions I didn't get a chance to really wind it out, but I think I would be OK with the stock power. It doesn't lift the front end with a simple blip of the throttle like my WR will, but it is pretty decent. I didn't get to climb any big hills with it.
The YZ250FX owner was pleasantly surprised at my WR450F at the first stop and said it was downright boring to ride at the second stop, because it made things so easy. He said he was just idling along. That is my impression of my bike too. This in conditions that had one YZ250 rider crashing in the staging area and hurting his wrist and another YZ250 rider get seriously sideways on the trail, though he saved it. Were the YZs too pipey for these conditions ?
The FX owner thought my WR's rear suspension was really good and the front suspension was too soft, both of which I agree with.
The other bike that was boring was a TE300 with a super sticky rear tire. I'll take it as a compliment to have my WR in the same boat with a TE300, especially since my WR had a worn (but sharpened) M5B on it.
One of the other riders had a 2013 KTM 350 XCF. He offered to trade. I didn't want to ride it in such slippery conditions, so I declined. But I twice caught him on technical hill climbs, which surprised me, though I ran at his pace or faster on the flats most of the day. I thought he was a better rider than I was. Maybe he had an inferior rear tire ?
I'm toying with the idea of buying the YZ250FX as a second bike. I'm not sure I could give up my WR. It feels heavier than the FX when you get back on it, no doubt. But once you forget that, it still handles really well and I do love, love, love that 450F power.
People say you never use the power of a 450F in tight woods, but I beg to differ. You use it all the time. Every log hop, every little climb, every acceleration from tree to tree. You might not get it wound out at WOT very often, though you still do from time to time but its the low and mid speed torque that you use all the time. I love how linear the throttle is on my WR. Like when climbing a hill in slippery conditions, how you can roll back the power, get it to hook up and then roll it on just a bit more and accelerate, all while remaining hooked up, without spinning out.
My overall impression of the YZ250FX is that its an excellent singletrack bike. Agile, planted, stable, good power (for a 250F). I'd love to have one as a backup to my WR450F.