KTM unleashes its 250F

by James Holter

Finally, we have a full gate.

While Yamaha, Honda, Kawasaki, Suzuki and even Husqvarna have been happily feeding riders’ cravings for the reasonable weight and ample torque of 250cc four-stroke motocrossers, KTM has only been able to offer up its 125SX two-stroke for the tiddler class.

Sure, the 125SX has been a leader in terms of sheer ponies, but if the number of 250Fs at the starting gates of motocross races around the country is any indication, riders prefer the four-strokes’ broad, smooth power curves.

KTM, or any manufacturer for that matter, hasn’t been able to woo many riders back to 125 two-strokes, but now the Austrian company doesn’t have to fret about it. There’s a 250F KaTooM to consider, as well.

KTM introduced its 2005 250SX-F to the motorcycle press at Perris Raceway in Southern California on Monday, April 25. (Contrary to some speculation, the bike wasn’t an early ’06 model. The 2006 250SX-F will be released, with updates, along with the rest of KTM’s ’06 lineup later this year.)

If initial impressions are any guide, the 250SX-F is a real threat in what’s becoming the most competitive class in motocross.

And there’s no question the little orange thumper can compete in terms of horsepower. Not only does the power carry smoothly into the upper rpms, but it’s delivered with some punch. It’s not like a two-stroke, of course, but for those of us whose lack of corner speed needs all the help it can get, the revs build quickly.

If those revs build too quickly, you don’t have to worry about running out of gearing with the KTM either. While the other manufacturers run five-speed transmissions in their 250Fs, the KTM 250SX-F has a six-speed close-ratio gearbox.

The 249.51cc cylinder is brought to life by four titanium valves driven by dual overhead cams. An intermediate lower cam gear behind the water-pump impeller and hydraulic cam chain tensioners allow the use of a shorter cam chain that KTM says provides more consistent valve timing at all rpms.

There’s little engine braking — good or bad depending on your preference, but it’s not like you need it. The Brembo brakes stop on a dime.

Out back, the 250SX-F runs KTM’s trademark linkage-less rear suspension, which just makes sense in terms of simplicity and weight, especially because it works. The forks felt a tad harsh, but planted the front wheel nicely through turns.

The KTM’s oval chrome-moly steel frame is rigid but forgiving down choppy straights. It has a 63.5-degree head angle, a 58.7-inch wheelbase, a 36.4-inch seat height and 15.3 inches of ground clearance.

Then there’s all the little stuff that KTM does that makes its production bikes some of the most ready-to-race that you can buy. Like other models in KTM’s lineup, the 250SX-F comes stock with 1-1/8 inch bars, frame guards, an X-ring chain, a feather-light and butter-smooth hydraulic clutch, wave brake rotors, dual-compound grips, and trick adjustable triple clamps that allow multiple bar positions. The bike is slim and component quality is solid.

Of course, a big consideration for a tiddler class racer, whether a 250cc four-stroke or 125cc two-stroke, is reliability. Unfortunately, one day at a factory-supported test ride on factory-prepped bikes doesn’t say much about long-term dependability, although no major problems were apparent.

That said, the valve train is about as simple as it can get.

KTM mounted the spark plug on the side of the head to clean up the space up top, and the separate cam housing can be removed for easy access. Checking your four-stroke’s valves is never going to be a fun job, but KTM engineers made it as straightforward as possible. Heck, they even angled the base of the magnesium cam cover so it can be more easily removed with the engine in the frame.

While initial impressions really can’t tell you where the bike stands in terms of the competition, there is no doubt that the 250SX-F can compete. Team Red Bull KTM riders have been successfully contesting the THQ AMA Supercross series on the four-strokes.

Josh Hansen nearly pulled off the AMA 125 East Championship on one, tying Grant Langston in points but losing the championship in tie-breakers. And, in the West, Nathan Ramsey was holding off Andrew Short for second in points, with one round to go, and likely would have taken his title fight with Ivan Tedesco to the last round if not for a DNF in Phoenix and a 20th in San Francisco.

With the KTM 250SX-F clearly a contender, especially in the engine department, expect some orange on the podium when the outdoor nationals get started. And with production models on their way to U.S. showrooms, it’s not just the Team Red Bull KTM riders who can celebrate.