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MXA’S 2014 KTM 250SXF MOTOCROSS TEST: IT ROMPS ON THE DYNO, BUT WHY DONT WE LIKE IT ON THE TRACK

March 11, 2014
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FIRST AND FOREMOST, IS THE 2014 KTM 250SXF BETTER THAN THE 2013 KTM 250SXF?

A: Yes, but we’re splitting hairs. The engine is unchanged, but the suspension, front brake and map settings were breathed on by KTM’s engineers. The 2014 KTM 250SXF is remarkably similar to the 2013 model, but the Austrians did make enough revisions to warrant the accolade of “better.”


Q: WHAT APPROACH DID KTM TAKE WITH THE 250SXF?

A: KTM has been—and always will be—a motorcycle manufacturer focused primarily on engine development. How can we make such a bold statement? KTM’s fleet of motocross-bred bikes, from two- to four-strokes, pump out serious ponies on the dynamometer. The Austrians’ efforts should be applauded by the MXA wrecking crew, but instead we’ve grown leery of their “more power!” mantra. While this approach has done wonders for the KTM 450SXF and 350SXF, the 250SXF leaves a lot to be desired. How is it possible to have the most power but be left wanting? It’s one thing to have the fastest bike in the class, but it’s another thing to have a powerband that is focused and usable. The 250SXF is able to hit the high notes, but it lacks the baritone needed to create harmony. The 250 class is won and lost based on one key element: the powerband. It’s true that a bevy of other factors account for the overall package—suspension, handling, brakes and ergonomics—but it all boils down to which bike has the best engine. The KTM 250SXF falls short.



Q: WHAT CHANGES WERE KTM’S ENGINEERS FOCUSED ON?

A: The list is not extensive. KTM feels content with their 250SXF package, so they made minimal changes to problematic areas instead of rebuilding from the ground up. Refining a motorcycle that has many redeeming qualities is a good idea for several reasons. (1)
The engineers can focus on key issues rather than tweaking the whole package. (2)
Good attributes of the bike aren’t lost to the dumpster.


Q: HOW MANY CHANGES DID KTM MAKE TO THE 2014 250SXF? LET US COUNT THEM:


A: There are eight changes of note on the 2014 250SXF:

(1) Swingarm.
The chain guide mounts on the swingarm have been stiffened (the previous design was prone to bending when the chain guide dragged through deep ruts). KTM redesigned their chain guide, which is smaller, flexes more and is 120 grams lighter.

(2) Suspension.
The 48mm WP closed-cartridge forks have revised valving settings. KTM wanted greater resistance to bottoming, more traction and more comfort. It should be noted that our research leads us to believe that the fork-oil height and valving are the same on the 250SXF, 350SXF and 450SXF. The only difference is in the spring rate.

(3) Engine.
KTM retained the double-overhead camshafts and DLC-coated finger-followers, but they’ve devised a new water-pump cover and gasket for a better seal. The starter freewheel assembly has also been optimized for increased durability and longevity while relieving engine braking.

(4) Transmission.
The KTM 250SXF had long been distinguished by its six-speed transmission. That’s no longer the case. KTM removed sixth gear. The weight savings is considerable—250 grams, or slightly over a 1/2 pound. The gear ratios remain unchanged.

(5) ECU settings.
KTM revised their mapping to eliminate the popping and backfiring that the 250SXF suffered under deceleration. They also targeted the lazy feeling in the bottom end. These issues were alleviated in the base map, but the 250SXF also has a soft map (map 1, with 1 degree of advanced timing taken away from stock) and an aggressive map (map 2, with 1 degree of advanced timing added to the stock setting). These settings can be changed by an optional map switch found underneath the seat. Additionally, the wire harness has been simplified and upgraded with higher-quality wires and connectors. Not only that, but all fittings are enclosed in rubber boots.

(6) Front brake.
A Brembo front brake again comes standard on the 250SXF; however, KTM made several revisions to what we deem the most powerful front brake on the planet. The master cylinder has a new reservoir, a new lever, optimized kinematics (a fancy word for motion) and a smaller piston diameter (down from 10mm to 9mm) for greater braking power. Revised brake pads also aim at increasing performance. In the aesthetics department, the master cylinder and reservoir have been sand-blasted (giving both parts a bright sheen), and both caps are black.

(7) Gas tank.
The 250SXF has a 1.98-gallon fuel capacity and a new low-profile gas cap with revised threads. This update comes after KTM discovered that the old cap wouldn’t seal properly over the course of long, hot motos when the gas tank expanded.

(8) Aesthetics.
The 250SXF again comes with in-mold graphics, with the 2014 design inspired by the KTM race team. The shrouds, air-filter cover and winglet graphics above the shock bladder receive the in-mold treatment, which is very durable. KTM swapped the orange Renthal FatBar bar pad for black, and the handlebar grips are a slightly softer compound.


Q: WHAT WAS THE MOST REDEEMING QUALITY OF THE 2013 KTM 250SXF THAT MXA TEST RIDERS STILL TALK ABOUT?

A: The 2013 KTM 250SXF produced the most horsepower in the class by leaps and bounds. It broke the 40-horsepower barrier, climbing the dyno chart until it peaked at 42.89 ponies at 13,500 rpm (with 20.20 foot-pounds of torque). No other bike in the class, aside from the Kawasaki KX250F, even came close to producing as much power as the 250SXF. We’ve tested full-blown race bikes that couldn’t hit those statistics with engine modifications and a new exhaust system.



Q: DOES THE 2014 KTM 250SXF STILL PRODUCE INCREDIBLE HORSEPOWER ON THE DYNO?

A: It had better, given the fact that KTM didn’t make any changes to the cylinder, camshafts, valve train, crank or exhaust. Our 2014 KTM 250SXF reached 41.92 horsepower at 13,500 rpm, with 19.69 foot-pounds of torque. It doesn’t take a mathematician to discern a difference between the two model years. The 2013 model produced one more horsepower with slightly more torque. Why the inconsistency? There are several factors at play: (1)
The 2013 and 2014 bikes weren’t run on the dyno on the same day, so atmospheric conditions were different. (2)
Perhaps the 2013 model had a slightly longer break-in cycle (KTM admitted that their four-strokes produce the best dyno numbers after five hours of run-time). In the end, we raced the 2014 KTM 250SXF a couple of times and then took it back to the dyno—where is virtually duplicated its 2013 numbers. It is safe to presume that the 2014 engine can still get close to cracking the 43-horsepower mark. It should be noted that we tested the various mapping options on the dyno, but the aggressive and soft maps didn’t have any impact on the dyno curve.

We love the KTM 250SXF’S quick release gas lines (and the fact that the fuel lines have a replaceable filter, the white insert, in them).





Q: WHAT DO WE THINK ABOUT THE ELECTRIC STARTER?



A: Here’s a little known fact: in 2010, the kickstart KTM 250SXF had the prized distinction of being the lightest 250 four-stroke in the class. At 212 pounds, it was a featherweight in a field full of porkers. That’s no longer true. KTM took the technological equivalent of a few too many trips to the all-you-can-eat buffet. They added electronic fuel injection, linkage and an electric starter. As a result, what was once the lightest bike in the class became the heaviest.

KTM felt compelled to add EFI and linkage due to consumer demands. The push-button electric start came after the Austrians first experimented with it on the 450SXF. It was met with praise, so they put a battery and starter system in the 250SXF in 2012. In a two-year span, the bike gained over 15 pounds.

Motocross racers spend thousands of dollars to decrease the weight of their bikes, yet MXA test riders—and we assume every KTM 250SXF owner—wouldn’t trade electric start for the world. Once you push the button, you’ll know why. KTM’s electric starter is heavy, but it’s also simple to use and incredibly consistent.


Q: DOES THE 2014 KTM 250SXF PASS THE AMA SOUND TEST?

A: Does it ever! Our 250SXF purred at 114.2 decibels in the 115 dB two-meter-max test, well under the AMA maximum. As for the amateur-based AMA 94 dB sound test, the KTM passed at 93.9 dB. Don’t fret that it doesn’t pass the newly configured AMA/FIM 112 dB standards—those are only for professional racers.

 


Q: HOW FAST IS THE 2014 KTM 250SXF?

A: Not to be confusing, but the 250SXF is both fast and slow. How is that even possible? In the bottom end, when the engine has yet to get going, the bike is slow. Two-stroke enthusiasts can understand the following comparison: bogged down and under a load at low rpm, the 250SXF can’t get out of its own way; however, as the engine picks up steam through the midrange, the powerband starts to shine. At full tilt, which is above 13,000 rpm, the KTM leaves a vapor trail. It is eye-watering, hold-on-for-dear-life fast. The 2014 KTM 250SXF is not a bike for those short on speed or ability. It demands too much rpm for a rider who doesn’t have the talent to run wide open. Beginners, Novices and Vets should steer clear of the orange streak. On the other hand, this is the perfect bike for fast Intermediates, Experts and Pro racers who want an edge in the 250 class.

Can the 250SXF be effective in the hands of less-skilled riders? Yes, but it will take an investment. For starters, add at least one tooth to the rear sprocket, as the stock 13/50 combination is only advantageous at the Bonneville Salt Flats. Next, invest in an aftermarket exhaust system. We’ve tested several exhausts that are vast improvements over the stocker. We also recommend experimenting with the various maps. Most MXA testers preferred the aggressive setting (map 2), but the base or soft map might be more to your liking. Aside from these suggestions, the most effective way to maximize the KTM 250SXF powerband is by riding without regard for your personal well being. Keep your right wrist locked so that the throttle is wide open, and use the hydraulic clutch judiciously.





Q: HOW DOES THE 2014 KTM 250SXF HANDLE?



A: For years we’ve gone to the mountaintops of Glen Helen, desert-scape of Racetown, and orchards of Piru to laud the chromoly steel frame of the KTM 250SXF. It’s a work of art. The chassis doesn’t do anything peculiar, and while the 250SXF isn’t the sharpest-handling bike in its class, we enjoy the stability and precision that the steel frame offers. Fore to aft, test riders felt that the KTM was balanced, though this quality was somewhat masked by the flawed WP suspension. More on that below.


2014 KTM 250SXF: KTM’s 250SXF engine makes the most power of any bike in the class, but it is a high-rpm, hang-on-and-pray style of power that best suits fast Intermediates and Pros. If you don’t leave it on—you might as well not turn it on.


Q: WHAT DO WE THINK ABOUT THE WP SUSPENSION?

A: We don’t think very highly of it, at least not on the 250SXF. In what we believe was an effort to cut production costs, KTM outfitted all of their four-strokes with the same basic oil height and valving specs. You’ll notice in our 2014 KTM 350SXF test (found on page 88) that test riders were much more positive in their feedback of the WP suspension. That’s because the oil height and stiff valving are better suited to a heavier and more powerful bike. Unfortunately, these “comfort settings,” as described in KTM’s marketing literature, are too harsh for the 250SXF tiddler.

For years we’ve lowered the oil height by draining excess fluid out of the fork bleeder holes. This was a band-aid fix in that it lessened the mid-stroke harshness. Unfortunately, this remedy caused the forks to slam into the bottoming cones and hinder bottoming resistance. The be-all, end-all solution is to have the forks revalved.

We believe that the WP shock is decent, but it is hampered by the fork’s maladies. KTM has done a commendable job of dialing in the shock/linkage pairing, but test riders still complained that the shock had an uncanny tendency to step out over square-edged holes and jump-face kickers. The unpredictability of the shock resulted in more than a few white-faced test riders.


Q: WHAT DID WE DO TO IMPROVE THE 2014 KTM 250SXF?



A: Find satisfaction by making these changes:

(1) Map switch.
Experiment with the three map settings provided by KTM. The base setting comes standard and is found in maps 3 through 10 (the coupler can also be unplugged for the stock setting). Map 1 is best for hardpack or conditions where retarding the timing would be beneficial. Map 2, MXA’s favorite map, is aggressive. It advances ignition timing and provides more hit in soft terrain. By the way, these map settings are free.

(2) Dial in the suspension.
If you’re on a budget, reduce the fork oil height. Work in 5cc increments until you find a comfortable setting. Serious racers should ship their forks to a KTM suspension expert (we’ve had luck with MX-Tech) for a revalve.

(3) Gearing.
The stock gearing might work for the wide-open tracks of Europe, but it’s too tall for most American tracks. Gear the 250SXF down by adding one tooth (at least) to the rear sprocket.

(4) Add a pipe.
Buying an aftermarket exhaust should yield considerable power gains. The 250SXF doesn’t need more power, but it does need to move the power down into the midrange.

Pucker power: The best brake in motocross got a little better.




Q: WHAT DID WE HATE?



A: The hate list:

(1) Weight.
What was once the lightest bike in the class is now the heaviest. Newfangled technology is the culprit. The linkage, the fuel injection and the electric starter come at a 5-pound price for each item. It’s a Catch-22.

(2) Suspension.
It’s impossible to share the same basic valving and oil height with the KTM 450SXF and find comfort with the 250SXF forks. As a result, the shock also suffers.

(3) Engine.
We were captivated by the dyno numbers, but on the track, those stats don’t equate. The powerband is Pro-level only.

(4) Hardware.
Wood screws and Torx heads don’t belong on a motocross bike.

(5) Gearing.
It’s wrong, unless you’re trying to set a land-speed record.


 Glider: KTM downsized the chain guide to save weight.

Q: WHAT DID WE LIKE?

A: The like list:

 

(1) Handling.
The 250SXF chassis proves that chromoly steel shouldn’t be cast aside, even though aluminum is the popular choice.

(2) Clutch.
It’s smooth like butter. We love the hydraulic clutch.

(3) Brakes.
KTM revised the front brake system. This equated to stronger stopping power and much better feel. Nicely done.

(4) Aesthetics.
We love the in-mold graphics. And speaking of graphics, they are much more attractive than the wretched graffiti design of years ago.

(5) Sound.
The KTM 250SXF purrs like a kitten and passes the two-meter-max and 94 dB tests with ease.




Q: WHAT DO WE REALLY THINK?



A: We are impressed with how far the KTM 250SXF has come in the past five years. The Austrians have built a thoroughbred engine that is capable of taking on the best bikes in the 250 four-stroke class. However, just as with any prized horse, the 250SXF comes with its share of headaches. The WP suspension settings are wrong, really wrong, and the bike is hefty, really hefty. Yet, while the KTM 250SXF may get out of the gate slowly, it would put a few lengths on Secretariat down the stretch because this bike screams on top. It’s just a question of whether you’re fast enough to sustain such breakneck speeds.


Little brother: If you’ve ever wondered why KTM’s little bikes have bad suspension and their big bikes have good suspension, wonder no more. It turns out that whether a 250SXF or 450SXF, they get the same fork valving. Only the fork springs are changed to protect the innocent.


  MXA’S 2014 KTM 250SXF SETUP SPECS            

Are you looking to get your 2014 KTM 250SXF’s suspension set up? Use these specs as a starting point and adjust accordingly.


WP FORK SETTINGS

We lowered the oil height by 15cc to alleviate mid-stroke harshness, but the only true fix is to send the WP forks out for revalving. They are too far gone for backyard fixes. For hardcore racing, we recommend this fork setup on the 2014 KTM 250SXF (stock specs are in parentheses):

Spring rate:
0.46 kg/mm

Oil height:
375cc (390cc)

Compression:
11 clicks out (12 clicks out)

Rebound:
10 clicks out (12 clicks out)

Fork-leg height:
5mm up

Notes:
When the forks are new, they need about an hour of riding to break in. Lighter riders might want to lower the oil height by an additional 5–10cc, depending on skill level. Decrease the oil height until the mid-stroke harshness is gone, but not by so much that bottoming occurs.


Rule: Save some money to have the forks revalved by a professional.

WP SHOCK SETTINGS

The only change to the KTM 250SXF shock for 2014 is one less compression shim in the stack. KTM did change the way they bleed the shock, which they claim will improve performance right out of the crate. We discovered that the 250SXF still has a tendency to hop and deflect on square-edged bumps. After trying a bunch of different settings, we discovered that dialing in the shock required slowing down the rebound and high-speed compression and setting the sag a little lower to take some of the spring out of the compression equation. Oh yeah, avoid square edges whenever possible.

For hardcore racing, we recommend this shock setup on the 2014 KTM 250SXF (stock specs are in parentheses):

Spring rate:
5.4 kg/mm

Race sag:
105mm

Hi-compression:
1-3/4 turns out (2 turns out)

Lo-compression:
15 clicks out (16 clicks out)

Rebound:
13 clicks out (15 clicks out)

Notes:
The shock is very sensitive to sag and getting it to work depends on making careful use of the spring rates, damping and setup choices at hand.

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