I was scouring the internet searching high and low to get an honest review from a normal rider without any bias like you get from moto magazines. There isn't one in existence at the moment. When I got the Yamaha's 2 years ago I swore I'd stick with Yamaha I loved them that much, I also said the same thing about my KTM 300's and 350 before that and I'm sure I'm going to say exactly the same thing about the 250SXF and 250XCF when I get that one in February.
For the last 2 years I have been riding a YZ250F for MX and a YZ250FX for off road. I have absolutely loved the Yamahas and they have both been very reliable with only 2 minor issues to do with a MAP sensor. The handling of both the Yamaha's was so good out of the box all I did was change the springs to suit my 100kg weight. The power delivery of the YZ250F was fantastic, linear all the way through the rev range with good torque from low to mid and it made it a fairly easy bike to ride.
The YZ250FX had a similar power curve to the YZ250F however it was a little bit "lazy" of the bottom and even when slipping the clutch it could take a while for the power to come on, I put this down to the heavier flywheel weight. It also seemed to sign off a little bit early and you had to be right on top of the gear changes.
Now onto the KTM 250SX-F:
Well I'm one ride in and I've got an hour and a half on the hour meter. The first thing I did when I got the bike was to try and find out the correct PSI to put in the air forks for my weight of 100kg. I could not find a figure anywhere on the net, only the figure of 154 in the manual which is supposed to be for the 75-85kg rider. So I set it to 158 and thought that would be a good base. Within half a lap I knew that it was too much so I came straight back in a dropped it to 144. I thought that this setting would be too soft but I wanted to get the extremes of high and low to make it easier for me to find a middle ground. So after a couple of laps on the 144, I cam in and set it to 154 and it felt pretty close to right but it was difficult to tell as all the ergos are a different to the Yamaha's so while I was trying to adjust to the ergo's and the difference in power delivery the suspension became the last thing on my mind which is a pretty good sign.
That gets me onto the real difference between the KTM and the Yamaha. The 250SX-F pulls to the moon and it pulls hard. As a side effect of this, it isn't as torquey off the bottom and mid. At first, I thought all the reviews I have read about the 250SX-F being a monster up top was bullshit it felt slow and took a while to build. Then I changed my riding technique to ride it higher in the rev range than I would with the Yamaha and in a lot of cases I was running a gear lower than I was used too in corners and I was instantly rewarded. At first, I still thought hmmm, I was expecting more from the power after all the reviews I read about it. Then as I rode it more and actually rev'd it to the limiter through the gears I started coming into corners way too hot and overshooting corners. Deceptively quick and almost reminds me of being ridding a 2t pinned.
I will have more to update soon, I've got the suspension going into to SPMX this Thursday to get it sprung for my weight and then I'll have a really in-depth look at the forks and shock.