2009 KTM 250SXF; Suspension Settings, Jetting Specs, Likes & Dislikes, Plus Much More
INSIDE THE MXA 2009 KTM 250SXF TEST
Finishing last in MXA’s 2008 250F shootout might sound like failure, but in reality, last year’s KTM was oh-so-close to moving into the top three. Close, but no cigar! The Austrians had a lot going for them in 2008. The KTM 250SXF made the most peak horsepower, and it was the lightest 250 four-stroke ever made. Yet, even with those two superlatives, it got a big goose egg from the MXA test riders. Why? Because the 2008 KTM 250SXF was poorly suspended, suffered from gearing issues, and the engine, while impressive on the dyno, was anemic on dirt.
You have to give KTM credit. In the good old days, the Austrians would have dismissed MXA’s criticism as spoiled American whining and kept building what they were building-?no matter what. Not so for 2009. KTM went back to the drawing board in an effort to work out the bugs. They promised the MXA wrecking crew that while the 2009 250SXF looked like a carbon copy of the 2008 version, it was changed in the places where it mattered most. The MXA wrecking crew set out to find out if that was true.
Q: WHAT’S NEW FOR 2009?
A: We didn’t like last year’s engine. So shoot us! Most MXA test riders felt that the 2008 powerband was listless off the bottom, slow to build steam through the middle, and the top-end power it did make, it made too late to do much good. KTM must have agreed. While the 250SXF still retains the same frame, swingarm, gearing, triple clamp offset and plastic, KTM focused their attention on the engine. Thanks to new beehive valve springs, sleeker valve guides, lighter titanium valves, thinner finger followers, a smaller cam chain and a downsized camshaft, the complete valve train is considerably lighter. This is smart engineering, because the lighter the running gear, the snappier it responds to changes in engine rpm. And the 2009 KTM engine can be described with one word-?lively.
Q: WHAT ELSE IS NEW FOR OH-NINE?
A: There are several improvements to the chassis and the suspension.
Chassis: A different compound has been used in the brake pads (to make them less grabby), and the brake master cylinder piston has been decreased to 9mm. There are also new brake calipers, black machined triple clamps, a front brake lever, shroud design (the shrouds are tucked in to allow for more rider movement), Regina chain, frame guards, head stay and ignition and clutch cover.
Shock: KTM went up in spring rate on the shock. They also incorporated a larger inlet passage through the shock’s piston (from 11.5mm to 14mm). The piston ports were reshaped to improve oil flow between the pistons on high-speed movement. For 2009, the needle that activates the second piston comes into play much later in the stroke. In essence, the second piston is used as an anti-bottoming device.
Forks: WP found a new supplier for its upper fork stanchions. The new tubes, no longer black anodized, are 0.4mm thinner, lighter and tapered to feed more flex into the front end under loads. Additionally, the Japanese-sourced chrome fork legs have thinner walls for more flex. KTM also dropped the oil height by 5cc in the forks (from 390cc down to 385cc) and used 25mm shorter bottoming cones (to give more bottoming resistance).
Q: HOW FAST IS THE 2009 KTM 250SXF?
A: What a difference a year makes. This baby is a screamer! Every single test rider came away impressed with the KTM 250SXF’s engine, especially after riding it back-to-back against the 2008 KTM 250SXF. The two engines were hardly comparable, aside from the overall power. The 2009 engine is much more responsive through the middle, doesn’t give up the ghost until well into the top end and has plentiful over-rev.
Last year’s engine made more horsepower than any other 250 four-stroke but felt so doggy that the amount of power didn’t matter. Thanks to the lighter valve train and new ignition, the 2009 KTM 250SXF has a good shot at taking the throne with a better hitting and broader powerband. It should be noted that a lighter valve train doesn’t show up on the dyno-?only the racetrack. This engine is strong, fun to ride and a very good race engine.
Lightening up the moving parts (valve springs, valves, guides, finger followers, camshaft, cam chain and cam gears) gives the 2009 KTM 250SXF engine plenty of power at the lower echelon of the curve (unlike the 2008 bike). To summarize, the MXA wrecking crew would pick the 2009 KTM 250SXF engine over the 2008 engine in any conditions and on any track.
Q: HOW MUCH HORSEPOWER DOES IT MAKE?
A: The 2009 KTM 250SXF pumps out 38.6 horsepower. For comparison, that is about one to three more horses than a Suzuki RM-Z250, Kawasaki KX250F, Yamaha YZ250F or Honda CRF250. That is impressive. Even more impressive is the KTM’s over-rev. Unlike any other 250 four-stroke, the 2009 KTM 250SXF makes its peak horsepower almost at its peak rpm. That means that as long as the engine is revving, it is making more and more power. The KTM’s peak horsepower is at 12,800 rpm.
Q: WHICH MODIFICATION DOES THE 2009 KTM 250SXF BENEFIT FROM THE MOST?
A: Gearing. In 2008, we geared the bike down by two teeth to maximize the engine’s potential. KTM didn’t touch the gearing for 2009, so we automatically assumed that adding at least one more tooth to the rear sprocket was in order. We were right. Despite the fact that the engine’s throttle response is considerably better than on last year’s powerplant, we still needed to jump from a 48-tooth sprocket to a 49 to close the gaps between second, third and fourth gears. Slower riders (or those who ride very tight arenacross style tracks) might even opt for an additional tooth on the rear.
Q: HOW IS THE JETTING?
A: Initially, there was a hesitation off the bottom, most noticeably after the engine warmed up. After messing with the fuel screw (and not making much headway), we made a big adjustment to the accelerator pump, and that solved the problem. The 39mm Keihin FCR carburetor comes with a leak jet for fine tuning (KTM has not used leak jets in the past). MXA’s recommended jetting is as follows (stock settings are in parenthesis):
Main: 175
Pilot: 40
Needle: OBEKP
Clip position: Fourth from top
Fuel screw: 1/4 turn (1 turn)
Notes: KTM switched from an OBETP needle in 2008 to a OBEKP for this year, which is substantially richer. On the accelerator pump, we turned the screw in until it made contact with the pump and then backed it out 1/4 of a turn. In our experience, fiddling with the adjustment screw pays big dividends on the KTM carb. From the contact point, back the adjustment screw out (counting turns as you go). This is a must-do adjustment.
Q: ARE THE KTM’S WP FORKS AS GOOD AS JAPANESE FORKS?
A: Are the WP USD forks up to the standards set by Yamaha’s SSS system? No. In stock trim, the WP forks are extremely harsh in the midstroke and fail to budge in small chop. Every wrinkle or bump in the track is transmitted directly through the forks and into the handlebars. The MXA wrecking crew complained about the same problem on the 2008 250SXF, and we fixed the midstroke harshness by lowering the fork oil height by 20cc.
For 2009, KTM listened to one of our complaints and dropped the fork oil height by 5cc. They also utilized shorter bottoming cones to give the forks more bottoming resistance, but these subtle changes made little improvement to the feel of the forks at midstroke. We felt compelled to drain 15cc of oil out of the forks, which allowed the new bottoming cones to do their job as the forks began to use their full travel. Suffice it to say that once you achieve the proper oil height, the Dutch-built, 48mm WP forks worked reasonably well.
Q: WHAT ARE MXA’S RECOMMENDED KTM 250SXF FORK SETTINGS?
A: Here is what the MXA wrecking crew ran in its 2009 KTM 250SXF. Stock settings are in parenthesis:
Spring rate: 0.46 kg/mm
Oil height: 370cc (385cc)
Compression: 16 clicks out (15 out)
Rebound: 20 clicks out (19 out)
Fork leg height: 5mm up
Notes: When the forks are new, they need about an hour of riding to break in. Smaller riders might opt to lower the oil height by 20cc (from stock).
Q: WHAT DID KTM CHANGE ON THE REAR SUSPENSION?
A: Let us preface our answer by stating that three years ago we complained that the 2007 KTM 250SXF was undersprung (it was outfitted with a 6.3 kg/mm spring). In 2008, KTM answered our complaints by raising the spring rate to 6.6 kg/mm. We complained some more and actually ran the stiffer shock spring off of our KTM 450SXF on our 2008 250SXF. For 2009, KTM stepped up again by spec’ing a 6.9 kg/mm spring. We welcome this change. Still, the shock spring only worked well for very fast and very fat riders. It’s a racer’s spring rate, meaning that slower and lighter riders might opt for the previous 6.6 kg/mm spring rate.
Q: WHAT IS MXA’S RECOMMENDED KTM 250SXF SHOCK SETTING?
A: Here is what the MXA wrecking crew ran in its 2009 KTM 250SXF. Stock settings are in parenthesis:
Spring rate: 6.9 kg/mm
Race sag: 110mm
Hi-compression: 1-3/4 turns out (1 turn out)
Low-compression: 12 clicks out (15 out)
Rebound: 19 clicks out (22 out)
Notes: We recommend running between 107 and 110mm of sag to maximize the shock’s potential. Also, if you have trouble getting 30mm of free sag and 110mm of race sag at the same time, consider changing to the lighter 6.6 kg/mm shock spring.
Q: HOW DOES THE 2009 KTM 250SXF HANDLE?
A: We didn’t like it very much. Why not? Right out of the crate the 2009 KTM 250SXF suffers from a number of maladies that hamper handling. The biggest culprit is the forks. Their mid-stroke harshness doesn’t allow the front end to settle into corners. The forks contribute to an irritating amount of headshake at speed and imprecision at the entrance to turns. Because the forks fought the chassis, a lot of the load was transferred to the KTM’s PDS shock. It kicked, bucked and bolted in consecutive bumps.
Q: CAN THE HANDLING BE FIXED?
A: Even a great handling chassis can’t work if the suspension doesn’t do its job. Our quickest fix, for both the suspension and the handling, was to dial in the forks. We used bottoming as a guide. We lowered the oil height until the forks bottomed and then added 5cc of oil back. With the forks stroking fully, we were able to find ballpark clicker settings (and amazingly, the shock started to work in unison with the forks).
With these changes the KTM 250SXF handled quite well. The bike remained planted in corners, didn’t understeer, and straight-line stability was improved. Our only complaint about the handling (and we voiced this complaint on last year’s bike) was how the shock reacted when the chassis was unloaded. The rear end had a tendency to step out, particularly in braking bumps. Interestingly enough, this problem wasn’t evident when the throttle was applied.
Q: WHAT DID WE HATE?
A: The hate list:
(1) Forks. We’re getting sick of pulling out the syringe every time we get a new KTM 250SXF. There is no reason why we should have to drain oil out of the forks every year. KTM should do it at the factory.
(2) Hot-start lever. The lever itself works well, but it is exposed to damage in a crash. Even worse, when it breaks it can also crack the clutch master cylinder cover, making it an expensive fix.
(3) Side panels. We don’t like side panels that won’t hold full-size numbers. KTM heads the list of offenders. Thankfully, for 2009 they extended the number plates forward onto the airbox lid, but it’s a Band-Aid at best.
(4) Gearing. KTM isn’t the only manufacturer guilty of needing to add an additional tooth to the rear sprocket, but they need it more than any other bike. If you don’t gear your 250SXF down, you will never get full use out of the engine.
(5) Carburetor. The 39mm Keihin carb blubbered off the bottom. We had to tinker with the accelerator pump adjustment screw more than we liked.
(6) Torx bolts. We don’t hate six-point Torx bolts, but they have no place on a motocross bike. Also on the complaint list is the fact that KTM still uses 11mm and 13mm hex head bolts. Those aren’t standard-issue T-handle sizes.
(7) Graphics. KTM’s graphics look like the designer was trying to write a ransom note on the shrouds. What does the note say? “These graphics are ugly!”
(8) Seat height. The bike is too tall.
Q: WHAT DID WE LIKE?
A: The like list:
(1) Front brake. The Brembo brake system, with a Galfer wave rotor, is a great brake. Not as powerful as last year, it is still a works-style brake that allowed test riders to go deeper into corners. Good stuff.
(2) Hydraulic clutch. After all these years KTM is still the only manufacturer of the Big Five to use a hydraulic clutch. The Magura unit is butter smooth and doesn’t fade over the course of a moto. Amazingly, the KTM 450SXF, which also has a hydraulic clutch, uses a Brembo unit.
(3) Transmission. The KTM is the only 250 four-stroke to come with a six-speed transmission. The added gear gives a rider more options, especially with the addition of an extra tooth on the rear sprocket.
(4) Triple clamps. KTM has the best triple clamps on the market. They are so good, in fact, that several aftermarket companies have borrowed from KTM’s original design. Not only do the KTM clamps have adjustable offset (18mm and 20mm) and four-mount bar positioning, but they even have the torque specs stamped on the upper and lower clamps.
(5) Engine. We must applaud KTM for their effort to refine the 250SXF engine by downsizing the valve train. The power plant has transformed a drawn-out, listless and uninspiring engine into one that is both fast and fun.
(6) Tires. Amazingly, the archaic Bridgestone M59/M70 tire combination is a fairly decent set of sneakers. The tires track well in soft-to-intermediate terrain and are predictable on hard pack.
Q: WHAT DO WE REALLY THINK?
A: We like the direction that KTM took in changing their 250SXF for 2009. The engine’s internals were given a high-tech overhaul, and the result is an overall package that is resoundingly better than in years past. The 2009 KTM 250SXF is a very good bike-?with demerits for the harsh forks, poor gearing and Keihin cough.
Check out the 2009 250F Shootout
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