Motorcycle specifications KTM250 SX-F 2018 The instinct to dominate

The KTM 250 SX-F has dominated the MX2 world championship for several years now, and has just added another world championship title to its impressive list of achievements. Who could steal its thunder? The KTM 250 SX-F combines a powerful, torquey engine with a light, easy-to-handle chassis, and flies from podium to podium.

eNGINE

the engine of the KTM 250 SX-F is considered one of the most powerful in the MX2 paddock. Capable of reaching 14,000 rpm without flinching, and with phenomenal torque present throughout the rev range, this engine has a lot to say for itself. Its compact architecture ensures better mass centralization and exceptional roadholding. It weighs just 26.1 kg, including electric starter.

hEADER

the centerpiece of the compact DOHC engine, the new avant-garde cylinder head features two overhead camshafts titanium valves using ultra-light, DLC-coated rockers.

cRANKSHAFT

the crankshaft of the KTM 250 SX-F uses a shortened connecting rod. More compact and lighter, the engine also gains in responsiveness. The crankshaft features a connecting-rod bearing and two bearing shells press-fitted directly into the crankpin. This bearing is supplied with oil from the engine's pressure lubrication system. This type of design, combined with the connecting-rod bearing, greatly extends the crankshaft's service interval.

gEARBOX

to enhance the reliability of the 5-speed gearbox, the surface of the pinions has been specially treated for 2nd, 3rd and 4th gears. The "zero dirt" design of the selector prevents the lever joint from clogging and jamming, and guarantees ultra-precise gear changes even on the muddiest terrain. All SX-F 4-stroke engines feature an engaged-gear sensor that adapts the engine's characteristics to each gear. On the AM18, the gearbox shaft features a new C4 bearing with increased radial clearance. This enhances reliability, even under the most demanding operating conditions. Enough to get you out of the sand in the middle of a Grand-Prix.

eLECTRIC STARTER

the KTM 250 SX-F comes with an electric starter as standard, a decisive advantage when it comes to reducing lap times in competition. Operated at the touch of a button, this ultra-powerful electric starter made by Mitsuba won't let you down, especially as it now features an O-ring seal capable of withstanding extreme temperatures.

mOTOR HOUSINGS AND COVERS

the design of the molded crankcases has a dual purpose: maximum weight reduction and a highly centralized shaft configuration for even greater engine compactness and more efficient weight distribution. The new crankcase covers feature a solid surface structure designed to reduce wear caused by the rider's boots. As a result, the SX-F retains an eternal air of youthfulness.

cYLINDER AND PISTON

the shortened cylinder, with a 78 mm bore, houses a proven bridge-box piston manufactured by CP. The geometry of the piston head, perfectly adapted to the new high-compression combustion chamber (14:1), features a rigid structure and reduced weight. The reduced oscillating masses give the engine its playful, muscular character.

bALANCER SHAFT

the side-mounted balancer shaft performs a dual function, driving the water pump at the same time. Thanks to perfect balancing and reduced oscillating masses, engine vibrations are reduced to a minimum.

eNGINE MANAGEMENT SYSTEM

the Keihin engine management system with electronic fuel injection features a 44 mm throttle body. Thanks to the injector's unique position, engine response is instantaneous. And for added convenience, there are independent adjustment systems for cold start and idle. The ultra-lightweight control unit manages a unique traction and start-up control system to give youand optimum driveability thanks to different engine maps adapted to the gear you're in. A more powerful engine mode, selectable via the switch on the handlebars, even enhances the aggressive character of your machine.

eMBRAYAGE

the KTM 250 SX-F uses a CSS (Coil Spring Steel) clutch developed by KTM. a sturdy steel clutch housing, heat-resistant clutch plates and new nitrate-treated steel liners that are less prone to wear. The clutch is activated by a hydraulic system manufactured by Brembo, which plays an essential role in the clutch's progressiveness and smoothness.

cOOLING SYSTEM

kTM's proven integrated cooling system circulates coolant from the cylinder head via the frame wishbone to the aluminum radiators supplied by WP. Its incredible efficiency is due to improved management of internal airflow and advances in ventilation thanks to CFD (Computational Fluid Dynamics) calculations. The new radiator protections offer the advantage of better heat dissipation. This is all the more true in the presence of mud. Integrated into the front spoilers, these radiator guards are particularly useful in the event of an impact.

wEIGHT

the main objective of KTM engineers when developing the new generation SX was to reduce weight and improve handling. The result is clear: the current SX-F models are among the lightest and slimmest competition bikes on the market, even though the 4-stroke models are now equipped with a very low weight.this is despite the fact that the four-stroke models are now equipped with a highly beneficial electric starter, whereas competing models still have to be kick-started. It's a sign that a strong current is flowing between the bike and its rider.

fRAME

the high-tech chromium-molybdenum steel frame is a model of lightness, flexibility and handling.the high-tech chromium-molybdenum steel frame, a model of lightness, flexibility and maneuverability, offers excellent stability and diabolical precision when cornering. Thanks to its high torsional stiffness and low longitudinal rigidity, this frame better absorbs the energy generated by the front and rear suspensions when jumping or negotiating a bump. The ride is more comfortable and less tiring. The aluminum brackets that link the cylinder head to the frame are as light as ever. Side-mounted, they also help to limit vibration levels and refine the bike's trajectory in bends. The engineers can be proud of their work, as the frame is now one kilo lighter than the lightest competing frame on the market today. Every effort has also been made to facilitate maintenance and free up space for the fuel tank and other components. The ultra-light rear section, made of stable aluminum profiles, weighs in at less than 900 grams.

eXHAUST

complying with the noise emission levels recommended by the FIM is a real challenge for all manufacturers. That's why KTM has spared no effort to develop a state-of-the-art exhaust system. As standard, all 4-stroke models feature exhaust manifolds connected to a small additional chamber called the resonator. They are also fitted with a relatively short silencer, mounted as close as possible to the engine. This has the dual advantage of centralizing mass and enhancing driving pleasure. The internal design has also reached a significant degree of sophistication to keep noise levels well below recommended thresholds, while guaranteeing maximum rider sensations.

fOOTREST

sophisticated "zero-dirt" footrests prevent the pivot from fouling, even when riding in deep ruts. Riding position not high enough? No problem! The footrest mounting system on AM 2018 EXC models is 6 mm higher than on SX versions.

aIR FILTER HOUSING

the air filter housing protects the air filter from clogging and ensures optimum air flow. The cage housing the extra-large Twin Air air filter is totally rigid, helping to hold the system in place. The design is so simple that you could replace the filter even with your face covered in mud. And without the need for any tools. And in a matter of seconds.

gUIDON

when it comes to handlebars, KTM engineers have always known which way to go. Profiled and made of high-strength aluminum, these handlebars are no exception to the rule. It features rubber shock-absorbing pads and can be adjusted to two positions. The ODI handlebar is easy to change when needed, thanks to its glueless, wire-free mounting system.

oSCILLANT ARM

in addition to saving weight, cast aluminum is ideal for bending. The one-piece molding process eliminates the imperfections inherent in welding, guaranteeing a more homogeneous, but also more meticulous, manufacturing quality.

fUEL TANK

the ultra-light polyethylene fuel tank has a capacity of 7 liters. The internally threaded fuel cap ensures easy, reliable closure.

wHEELS

kTM engineers know a thing or two about wheels. Featuring ultra-light CNC-machined hubs and top-of-the-range Excel rims, these wheels guarantee maximum stability despite limited weight. They are equipped with latest-generation Dunlop Geomax MX 3S tires

fORK

another interesting new feature on this bike: the WP AER 48 inverted fork with air spring and separate damping circuits, developed by WP in close collaboration with KTM. The damping functions are on the right, the air spring on the left. The left fork arm features a double-chamber air cartridge system to prevent any loss of pressure. Should the outer seal leak, the pressure exerted inside the inner cartridge will hold the bike in position. The air spring is easily adjusted to the rider's weight using a single valve. No special tools are required: the standard pump will do the trick. The right-hand fork leg incorporates a cartridge specially designed to adapt to the type of damping required. Simply turn the 30-notch knob to the desired position (compression up and rebound down) to select the appropriate setting according to track conditions and rider preference. More comfortable and responsive than ever, this fork (with revised damping characteristics) is just waiting to be put through its paces.

fORK TIPS

high-quality CNC-machined fork crowns, which ensure ultra-precise front-end behavior, have been a KTM trademark for years. Two positions are possible for the handlebar trigger guard with shock absorbers. The hour meter indicates when it's time for an overhaul.

dAMPER

the WP shock absorber was developed with the frame and swingarm architecture in mind, as were the linkage system and the WP AER 48 fork. With its various machined and black-anodized components, this ultra-sophisticated shock absorber makes a strong impression compared to less well finished competing products. It features a new, confidence-inspiring tuning and optimized damping characteristics that go hand in hand with the front-end setting. The shock absorber's gleaming colors are typical of the WP brand.

bRAKES

these little jewels of technology are combined with Wave brake discs renowned for their lightness. More responsive, more efficient and more powerful than ever, Brembo brakes will cope with any situation.

hANDLEBAR-MOUNTED POWER CURVE BUTTON

all 4-stroke models feature a handlebar-mounted power curve switch that fulfills the following three roles: Activating traction control - Engaging start control - Selecting an alternative power curve (Standard or Advanced). Traction control is a feature found on no other competing model to date. It ensures more efficient traction when track conditions leave something to be desired. A simple press of a button and the job is done. This power curve change button also engages the start control. A successful start and you're guaranteed a holeshot. The operating principle is simple: the start control reduces the engine's maximum speed at the precise moment of take-off, to maintain better control of the machine. Press the two buttons when the engine is idling, and the EFI indicator lamp on the upper fork crown lights up to warn that the bike is in READY TO RACE mode. In addition to the standard engine maps, an even more powerful engine mode is also available. The future is here.

bATTERY AND WIRING HARNESS

the starter motor is combined with a powerful lithium-ion battery, which represents a significant weight saving compared to the previous model. The battery and wiring harness are grouped together in a compartment above the air-filter housing, so as not to be hindered by the electrical circuit when removing the buckle. Mechanics and DIY enthusiasts will appreciate this.

eLECTRIC STARTER

like all KTM 4-stroke motorcycles, the 250 SX-F starts at the touch of a button, an undeniable advantage when it comes to setting a new lap time.

cHARACTER

all KTM factory riders collaborated on the bike's design with KTM R&D specialists and the Kiska design agency, with a single watchword: to create perfect harmony between rider and machine. The result is convincing. Ergonomics and rider contact points have been carefully designed to enhance freedom of movement and comfort on the SX-F. The special shape of the front and rear mudguards guarantees maximum stability and minimum weight, thanks to a well thought-out structure and assembly. Best of all, they stay clean longer.

gRAPHICS

custom deco kit, Factory orange frame: every detail counts, because in this discipline, there's nothing more beautiful than a bike that stands out from the crowd.

Information and image credits: KTM