Motorcycle specifications KTM250 SX-F 2017 Podium power

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

eNGINE

the 250 SX-F's engine 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 camshafts that drive the titanium valves via ultra-light, DLC-coated rockers. New side mounting brackets (now made of aluminum instead of steel) have been introduced to secure the engine to the frame and save a few hundred grams.

cRANKSHAFT

the 250 EXC-F's crankshaft offers greater rigidity. The connecting-rod bearing features two bearing shells pressed directly into the crankpin. This design is the prerequisite for extremely high speeds and the unrivalled power of the 250 cm3 engine. This design increases engine life and extends crankshaft maintenance intervals - a benefit for the user in terms of time, effort and cost.

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

to balance mass forces, the 250 SX-F engine uses a multifunction balancer shaft that simultaneously drives the water pump and timing chain.

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 handlebar-mounted switch, even enhances the aggressive character of your machine.

mAP SELECTOR

another highlight of the four-strokes is the new, sophisticated, multifunctional engine mapping, which can be activated directly from the handlebars, and fulfils a triple function:
- Activation of traction control
- Activation of starting control
- Selection of 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 and better control of the bike during acceleration. This is all the more evident in wet weather. A simple press of a button and the job is done. This map selector switch also engages the start-up control. A successful start and you're guaranteed a holeshot. The principle is simple: start-up control reduces the engine's maximum speed at the precise moment you start, so you can keep better control of your machine. Press the two buttons when the engine is idling, and the EFI indicator lamp on the upper fork crown lights up to let you know that the machine is waiting for a sign from the rider to pounce. In addition to the standard engine maps, there's another, even more powerful engine mode for boosting the bike when the need arises.

eLECTRIC STARTER

the 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, Mitsuba's ultra-powerful starter is combined with a proven drive system.

eNGINE HOUSINGS AND COVERS

the design of the molded crankcases has a dual purpose: to reduce weight and to allow a highly centralized shaft configuration, making the engine even more compact and achieving a much more efficient weight distribution. The new engine covers feature a solid surface structure designed to reduce wear caused by the rider's boots.

cOOLING SYSTEM

kTM's proven integrated cooling system circulates coolant from the cylinder head via the frame triangle 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. Well thought-out radiator guards integrated into the front spoilers are particularly useful in the event of an impact.

cLUTCH

the new compact CSS (Coil Spring Steel) clutch features a wear-free, lightweight steel clutch housing and seven clutch plates with high heat resistance thanks to their steel support plates. Brembo's hydraulic clutch system ensures precise, easy modulation.

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 perfect gearbox reliability. All 4-stroke engines are equipped with a gear sensor that allows the engine characteristics to be adapted to each gear.

bATTERY AND WIRING HARNESS

as in the past, all SX-F engines feature the proven electric starter - a KTM exclusive and a major advantage in motocross competition. The starter is combined with an ultra-compact lithium-ion battery, claimed to weigh just 495 g, which represents a significant weight saving compared to before. The battery and wiring harness are now grouped together in a compartment above the air filter housing, to avoid interference with the electrical circuit when removing the rear section of the frame. Mechanics and DIY enthusiasts will appreciate this.

eXHAUST

meeting the FIM's recommended noise emission levels 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 manifolds connected to a small additional chamber called the resonance chamber. They also feature a shorter 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 FIM-recommended thresholds (112 dB(A) at 2 meters maximum), while guaranteeing maximum rider sensations.

98.2 kg

the main objective of KTM engineers when developing the new generation SX was to significantly 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, offering excellent stability and devilish precision in corners. Thanks to its high torsional stiffness and low longitudinal rigidity, this frame absorbs the energy generated by the front and rear suspensions when jumping or going over a bump. The ride is more comfortable and less tiring. The dropouts 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.

fOOTREST

sophisticated "zero-dirt" footrests prevent the gear selector from getting dirty, even when riding in deep ruts.

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, making it easier 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.

oSCILLANT ARM

as well as saving weight, cast aluminium is ideal for bending. The one-piece casting process eliminates the imperfections inherent in welding, guaranteeing not only 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.

hANDLEBARS

when it comes to handlebars, KTM engineers have always known which way to go. This NEKEN handlebar, with its high-strength aluminum profile, is no exception. It features rubber silent-blocks and can be adjusted to two positions. starting with AM 2017, the handlebar is secured by two clamps (lower part) and a new trigger guard (upper part) that improves torsional rigidity. It's also easier to replace the handlebars should they become bent after a nasty fall. right: an ODI vulcanized handle; left: the ODI lock-on handle, as comfortable as it is practical, thanks to its glueless, wire-free mounting system.

sADDLE

tailored to provide a comfortable support surface, this saddle is as durable as it is comfortable. For added pampering, riders will benefit from a new saddle cover on the AM 2017, designed to enhance grip and feel.

cOOLING SYSTEM

kTM's proven integrated cooling system circulates coolant from the cylinder head via the frame triangle to 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 well-thought-out radiator guards integrated into the front spoilers are particularly useful in the event of an impact. For KTM, every detail counts.

wHEELS

when it comes to wheels, KTM engineers know their stuff. Featuring ultra-light CNC-machined hubs and top-of-the-range Excel rims, these wheels guarantee maximum stability despite limited weight. They are fitted with the latest-generation Dunlop Geomax MX 3S tires, which are wider at the rear (110/90-19 instead of 100/90-19). The bike features an optimized secondary transmission (14/51 instead of 13/50).

fORK

another interesting new feature on this bike is the WP AER 48 inverted fork with air springs 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 leg 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. For AM 2017, it's also important to point out that the outer tubes of the AER 48 fork have been redesigned to optimize bending characteristics, provide more flexibility and limit friction forces. They have also lost 265 g, which is far from insignificant. More comfortable and sensitive than ever, these forks are ready to be put through their paces.

fORK TIPS

high-quality CNC-machined fork crowns have been a KTM trademark for years. Enabling precise steering, they significantly enhance the flexibility characteristics and, thus, the action of the fork. For AM 2017, the design of the upper fork crown has been revised to accommodate the new plungers. The handlebars, fitted with rubber silent-blocks, are secured by two clamps (lower part) and a new trigger guard (upper part) that improves torsional rigidity. Handlebar replacement is also easier, for example in the event of a fall. An hour meter on the upper fork crown indicates when it's time for maintenance or refuelling.

dAMPER

the WP shock absorber was developed with the new frame and swingarm architecture in mind, as were the linkage system and the WP AER 48 front 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 benefits from a new setting and a softer spring, which go hand in hand with the new front-end setting.

bRAKES

more responsive, more efficient and more powerful than ever, Brembo brakes are ready to face any situation. These little jewels of technology are combined with Galfer Wave discs, renowned for their lightness. For AM 2017, the rear brake pedal has been lengthened by 10 mm and the new brake pads are now less aggressive.

cARENAGE

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. Particular attention has been paid to ergonomics and rider contact points for maximum freedom of movement. The lowered saddle offers superior comfort, especially at the rear. The special shape of the front and rear mudguards is a perfect example of intelligent design: thanks to a well-thought-out structure and assembly, these mudguards guarantee maximum stability, while being lighter at the same time. Best of all, they stay clean longer.

Information and images: KTM