Yamaha has invaded KTM turf. This is war.
Yamaha has invaded KTM turf. This is war.

Until now, KTM has enjoyed free rein in the world of off-road competition. Yamaha and the rest of Japan’s heavy hitters pretended not to be interested in dirt—aside from the extreme ends of the bell curve: motocross bikes and trail bikes. That left KTM unchallenged to build high-performance hardware for off-road racing and hard-core riding. Bikes like the 250XC-F have the latest technology and the best performance that the Austrian factory can muster wrapped in an off-road package. That’s why that market has turned into a KTM-versus-KTM affair.
Yamaha, in the meantime, only offered mildly tuned trail bikes like the WR450F and WR250F for this segment. Now that’s changed. The YZ250FX is a focused racer with all the intensity of the YZ250F motocross bike, but it has electric start, a six-speed gearbox and off-road trappings. In other words, it’s a KTM hunter.

The KTM 250XCF has the same power output as the motocross version.
The KTM 250XCF has the same power output as the motocross version.

KTM’s 250XC-F might be called a niche bike, but it serves a very big niche. As far as the government is concerned, it’s a competition bike that’s imported under the same rules as motocross bikes. That’s in contrast to the KTM 250XC-W, which is classified as an off-road bike and meets EPA and CARB emission regulations. The fact that KTM subdivided the 250cc four-stroke off-road market into these categories shows just how serious the company is about covering every angle in the dirt world.
Technically, the KTM 250XC-F is very similar to the company’s 250SX‑F motocross bike. It’s what a racer would build if he wanted to race the motocross bike in a GNCC or a hare scrambles. It has a larger fuel tank, an 18-inch rear wheel, handguards, a kickstand and softer suspension. The only thing that a home-spun racer couldn’t make for himself is the semi-close-ratio six-speed gearbox, which gives the rider a wider speed range. Everything else is the same as on the SX; it’s a double-overhead-cam four-valver that uses a system of finger-followers between the cams and the valves. That helps push the redline to an astonishing 14,000 rpm. It has an electric starter with no provision for a kick-start lever. The fuel injector is a Keihin system with a 44mm throttle body. It has a hydraulic system that works a coil-spring clutch (one of the few KTMs not using the diaphragm spring clutch). For 2015 there were a number of changes, headlined by a reworking of the suspension. The fork has a smaller axle. The rear shock is longer, and the linkage is altered. That last change more or less cancels out the longer shock, so the end result is unchanged suspension travel.

The YZ250FX is the competition model, not to be confused with the WR.
The YZ250FX is the competition model, not to be confused with the WR.

Yamaha calls the YZ250FX a new model, but as with the KTM, most of the parts come directly from the motocross version, which was completely new last year when it got the reverse-engine treatment. The cylinder is angled rearward, and the head is turned around so that the intake is in front and the exhaust is in the rear. The idea is to centralize the heaviest parts of the bike and keep all the outboard areas nice and light. The configuration also allows the intake tract to drop straight down from the throttle body and intake, which is located where the fuel tank usually sits. The fuel cell is more rearward, virtually in the center of the whole machine. You have to peel off a little piece of the seat to get access to the gas cap.
The biggest changes between the motocross bike and the new FX are the addition of a sixth gear and an electric starter. KTM, of course, started off with an MX bike that already had both, making less work for itself. Yamaha elected to keep its kick-start lever and tolerate a few extra pounds. Understandably, the FX’s electrical system is quite different from the YZ’s. The EFI uses the battery to fire up the system, whereas the YZ has a capacitor. That means that if you decide to save a few pounds and remove the battery, the bike won’t work. The FX’s black box has a timer that shuts down the whole system if there’s no activity for a few seconds. The YZ’s black box has no such feature, a fact that we discovered the hard way. We swapped black boxes between the two models, and not only did the electric starter become inoperable, but the whole battery went dead overnight. The bike ran well, but only for a while. Lesson learned. Other changes between the two Yamaha 250s include different fuel mapping and a different muffler. The FX is slightly quieter. The fuel capacity is 2 gallons on both. That’s big for a motocross bike but small for an off-road bike.
When the Yamaha and KTM met in our 250cc motocross comparison back in the December 2014 issue, it was advantage Yamaha. The YZ250F was lighter and had better suspension; the KTM was faster on top. These two bikes have another story to tell. The Yamaha gained 17 pounds with the addition of the electric start, so now it’s the heavier of the two. The YZ250FX weighs 239 pounds without fuel. The KTM weighs 234 pounds. The Yamaha has a kick-start lever and the KTM doesn’t. The KTM has handguards and a larger fuel tank; the Yamaha doesn’t. With a 2.5-gallon tank, the KTM’s range is significantly farther. The KTM also has a hydraulic clutch, whereas the Yamaha’s is cable-actuated.
Both bikes have oversize handlebars and no-tool air-filter access. Neither of them has a spark arrestor and neither is EPA or CARB compliant. If you want an off-road sticker in a state that cares about such things, both companies have other models specifically for that. The bikes in this contest are racers and not especially quiet. They both pass a 2-meter max sound test easily, but in the real world the KTM is a little louder simply because it revs higher. Finally, there’s the price comparison. The Yamaha sells for $7890; the KTM is $8599.
Both of these bike are fast. They’re powerful, revvy and responsive. But, that doesn’t seem to hurt their trail etiquette. They both have enough low-end power to idle through slow-speed sections without any ill manners. The mapping is clean, and there are rarely any coughs, sputters or stalls. Of the two, though, the Yamaha is friendlier down low. It has slightly more torque and is more willing to answer the call at the right time. But, this is a close contest. Both bikes make much more torque than the 250 four-strokes of just two years ago, whereas in the 450 class there hasn’t been significant advancement in engine output for years.
Somewhere in the middle-rpm range the KTM catches up, then it pulls away. The KTM pulls harder and harder the higher it revs, and by the time it’s done, it has left the Yamaha behind. Decisively. This was a surprise. We knew that the KTM motocross bike was faster on top, but only by a slight margin. The gap is much larger between these two. The FX’s mapping and exhaust must be the reason. Yamaha gave this bike a Euro-spec YZ muffler, whereas the KTM has the exact same exhaust system as the U.S. motocross version.
In order to use that horsepower advantage, you have to ride the KTM aggressively. Keep it revving and it’s happy, but there are problems with that kind of approach. It encourages you to use the clutch, and the pull at the lever is much more difficult than that of the Yamaha. So much for hydraulics. The KTM also has more engine braking when you chop the throttle from high revs, and that makes the bike lurchy. We don’t particularly like the Yamaha’s off-throttle manners, either. When the throttle is chopped on the FX, it’s almost like you’ve hit the kill button. We’ve made progress with the Yamaha by remapping the ECU with the GYTR Power Tuner, but we’re still testing at this point. It seems to like more fuel down low.
KTM has had mixed results with the 4CS fork. In most cases it works better for off-road applications than it does for motocross. That’s the story here. We’re fairly pleased with the KTM’s front end. It’s softer than the MX version’s, and that seems to make all the difference in choppy terrain. We’ll go so far as to say that the 250XC-F’s fork is better on most natural-terrain motocross tracks than the SX-F’s fork. The softer valving absorbs just enough light impact to increase the comfort factor. Comfort isn’t always the same thing as effectiveness, though. If there are jumps or G-outs, the XC fork uses up too much travel too soon. The compression adjuster on top of the left leg accomplishes very little.
The XC’s fork would probably seem great if it weren’t up against one of the best forks in the world. The KYB SSS system on the Yamaha is excellent. Like the KTM’s fork, it benefits from softer spring and valve rates as far as comfort goes, but it doesn’t dive as much or collapse on a big hit. Just like in the MX world, Yamaha has a big advantage in front suspension. In the rear, it’s virtual parity between the two. The shocks work well in rocks and at slow speeds without giving up any performance in big whoops.
We were really eager to learn if there were any difference between the two in agility. Does the centralized mass of the Yamaha cancel out its extra weight? Perhaps. Sometimes the Yamaha felt lighter than the KTM; sometimes not. On those occasions when you find yourself airborne, the Yamaha feels lighter and smaller. But, when you’re going down a steep hill, you feel every pound. On top of that, the KTM has much better brakes. For the most part, though, the two bikes are equal in perceived weight.
We’ll give the Yamaha the edge in overall stability. We raced it at the Adelanto GP, where you often find yourself topped out. There was no headshake or wobbling to report. Some riders occasionally accuse YZs of not having a well-planted front end, especially in broad, sweeping turns. After all, the rearward cylinder and relocated fuel cell mostly result in less weight on the front wheel. That complaint never surfaced with the FX. Like the motocross version, it likes a throttle-on turning technique. The KTM is more neutral. It can coast through a turn, as well as blast through it. But, the KTM is also much busier at speed. It headshakes occasionally and keeps you on your toes.
The biggest surprise in this test is how high the bar has been raised. It wasn’t long ago that the 250cc four-stroke off-road market was in hibernation. The XR250 generation was gone, and the replacements from Honda, Yamaha and KTM never developed the same following. Now a third wave of 250Fs is here, and these bikes are far, far better than their predecessors. The Yamaha YZ250FX and KTM 250XC-F are sweet trail bikes that have the technology and performance to be raced without modification. They really are at home in both worlds, but they lean in different directions.
The KTM is more of a racer. It’s really all about horsepower here. The KTM’s motor has the output to run with the big boys. It can go hill-climbing with the 450s one weekend and go straight to an MX starting line the next.
Yamaha’s new challenger leans more toward fun riding. It’s more comfortable and easier to ride. The easy clutch pull, comfortable fork and forgiving powerband make it the favorite of most test riders. It’s not perfect, though. It needs more power on top to hang with the KTM, and it should have come with a bigger tank and handguards, but it’s $709 less expensive to start with. Is that extra room in the budget enough to attain true perfection? Maybe not, but close enough.

To read about the differences between the Yamaha YZ250FX and the Yamaha WR250F, click here.

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