One year ago there was a question in the minds of the Dirt Rider staff: Can the KTM 250 SX-F actually live while making the kind of power it does at such an amazing rev ceiling? Now the answer is clear. It lives just fine, thanks. A 250F with maximum motor and a generous life span is a very happy thing. But that isn't all. For 2007, the 250 Katoom baby-thumper has a spankin' new big brother, and every update, redo and improvement to the 450 chassis-minus the electric starting-is translated into Lite for the 250 SX-F. On the list are radically revised suspension and a stronger chassis as well as updated ergonomics and significant weight loss. While the engine package didn't get (or need) a full reengineering like the 450 earned, the 250 wasn't ignored, either. Ignition tuning, a smaller intake port, cams with more duration, a new airbox and airboot combine with a new exhaust system to produce a strong 250cc powerplant that is easier to ride while producing radically less sound.
On the track, the most noticeable of the changes are the additional roll-on power and the new suspension and related chassis changes. We say related because the somewhat angled bridge in the swingarm and the massive nature of the side frame spars have a strong effect on the suspension feel of the Katoom. To a lesser extent, the octagonal (four of the sides are rounded, so the bottom frame tubes are more like a round tube with four flat sides) lower frame tubes are part of the whole equation. A more radical shock angle changes the lever ratio on the suspension, so a softer spring can be utilized. That softer spring stores less energy, so the rear suspension's rebound feel under braking acts more like a linkage bike than ever before.
The overall action of the shock is more tunable. The rear wheel tracks far better through small acceleration chop, and the traction feel is very good. As we have come to expect, the control through fast, rolling whoops is excellent. We checked, and the SX-F was able to handle one rolling whoop straight at Racetown 395 in fifth gear-and that was with no drama for the rider. Rolling G-loads make up one weakness of the KTM PDS rear suspension because the shock faces a lot of movement but it doesn't have the shaft speed to bring the second shock piston into play. The shock can sometimes bottom on little rolling dips (midspeed) yet handle sky-shot jump landings (high-speed) without trouble. The trait is minimized with the '07, but heavier riders noticed more bottoming than they had on past models with stock springs.
Likewise, the sealed-cartridge WP fork has very different manners than the '06 open-cartridge fork. Small, aggressive chop and edges are still very noticeable, but the front end doesn't do anything untoward. Larger bumps, especially landing in them, are absorbed with little drama. Bottoming was a problem for some riders, and we tried a variety of compression-damping settings without eliminating the issue. The KTM guys had no real problems, but those making their first tentative steps away from Asian machinery were bothered more.
Whether you find fault with the suspension action or not, the '07 machine tracks much straighter without any tendency to kick to the side when reacting to heavy impacts. The more balanced and rigid chassis, the bike being easier for the rider to grip with the knees and the roomy standing ergonomics all help in a straight line. For some, the front feels active, but others weren't bothered. More sag helped here. Even some of the KTM faithful wouldn't object to finding a steering damper under the Christmas tree.
The steering invited no waffling. The new chassis cuts a fine, tight line with good feedback from the front. This KTM has far better turn manners on flat or bermed corners than its predecessors.
And then there is that new engine spec. The KTM is strong for a modified 250cc four-stroke and just silly for a stocker. Some of the Asian bikes have a bit more bite off the bottom, but in the mid, the KTM comes alive and pulls hard all the way until it doesn't. The reason for that is that this KTM doesn't use a rev-limiter. The engine just stops making power. Third gear seemed a little shorter than on some bikes, but fortunately, the KTM pulls hard from gear to gear, and third and fourth feel quite close. So the answer to not having the right gear at times is to shift. It has the right gear-it just may not be the gear you are used to using. Oh, and when you go to shift, or if you choose not to, the clutch will tattoo little smiley faces on your brain. The pull is light, and the engagement is smooth and easy to modulate. The difference between a good juice clutch and a cable one is big.
As always, the KTM is nicely detailed with all the good stuff. To recap: The improvements include a better motor that is easier to ride, improved handling and light feel, and better suspension. The KTM was competitive in '06, and the improvement is huge for '07. And now we know the engine will go the distance. There is a reason so many MX Lites class privateers choose KTM. Orange gives them a chance of a holeshot against the factory bikes and maintenance they can live with.