Open space: The airbox requires no tools to get into, and the
Twin Air filter is held in place by a spring steel hoop.
2013 KTM 250SX
jets in the supplied tool kit. We kept the stock 158 main, but installed a small 40 pilot jet. Depending on weather and riding conditions, the KTM 250SX could use a 160 main. Q: HOW DID THE 2012 KTM 250SX HANDLE? A: This bike is light. Not just because it weighs 217 pounds, but because the snappy throttle response and sharp rev make the bike almost jump out of its skin under acceleration. If you are getting off a four-stroke, the first thing you’ll notice about the KTM 250SX is that you can throw it around. It feels like a feather in the tough and tight stuff. This is a superb-handling bike—maybe a little too hyperkinetic for the old, stodgy or stubborn—but this is the way motocross bikes should feel. A KTM 250SX doesn’t plow through the bumps; it gets on top and stays there. Every MXA test rider raved about how accurate it was in the corners. Test riders could go wherever they wanted— and places they could never get to on a four-stroke. Q: DID KTM IMPROVE THE 250SX FORKS? A: The MXA wrecking crew has never been big fans of the suspension on the 250SX. Why not? Because it has come with Euro-spec suspension settings. What are Euro-spec settings? In a nutshell, they are extremely soft fork springs and a longer shock. We hated this setup and have always been mystified as to why the KTM 250SXF, 350SXF and 450SXF got the good American specs, but the two-stroke didn’t. For 2013 we don’t have to wonder anymore. KTM, in all their wisdom, has upgraded the 125SX, 150SX and 250SX to American specs. This is good news. Q: HOW DID THE 2013 KTM 250SX SUSPENSION PACKAGE WORK? A: It was so wrong in 2012 that it could only get better with the application of some real-world spring rates. With stiffer fork springs, the front end no longer dives under braking. There is more available travel to absorb bumps, whoops and square-edged holes. If you feel that the new stiffer spring rates are too stiff for your weight or riding style, try lowering the stock oil height from 380cc to as low as 360cc. Faster riders are going to need more compression damping and maybe stiffer fork springs, but for the mass majority of racers, the KTM fork setup is very good. As for the shock, by shortening the Euro-spec shock by 4mm, the rear of the bike is lowered significantly, which makes it feel more balanced in transitions. The compression damping was enhanced with more low-speed compression and less high-speed compression. The 5. 4 spring rate is iffy for riders above 175 pounds, so use free sag to determine if you need to go stiffer; several MXA test riders ran 5. 7 kg/mm springs last year. (Turn to page 102 to find out how to use free sag to determine the correct spring rate.) We installed a longer link to bring the rear even lower, which allowed us to slide the forks up in the clamps, which brought the whole chassis down. Q: WHAT DID WE HATE? A: The hate list: (1) Clutch spring choices. Oh, don’t get us wrong; we like the Belleville washer-equipped DDS clutch, but it comes with very few tuning possibilities. KTM does not offer different-rate Belleville washers—and we wish they made a stiffer one for clutch abusers. As it sits, we are able to change the spring rate of the DDS clutch by mixing and matching the thick and thin clutch plates that come in the 250SX package. The more thin ones you use, the stiffer the Belleville washer. ( 2) Seat foam. Most MXA test riders prefer to switch to the Acerbis X-Seat because they hate the soft foam on the stock KTM seat. And switching to the X-Seat is a major concession, because as soft as the stock seat is, that is how hard the X-seat is. Given their druthers, test riders would rather have a seat that is too hard over one that is too soft. ( 3) Shock preload ring. Hate it. For riders who are on the cusp of the stock 5. 4 kg/mm shock spring, they will quickly discover the limitations of the nylon threads on the WP preload adjuster. When it decides to stop turning, nothing will make it go a millimeter farther.
Big boy: The rear axle has been upsized to 25mm, but you
can still use your old wheels by changing axle spacers.