Motorcycle specifications KTM250 SX-F 2020 Start of assault

At Katoche, the 4-stroke cross-country rhythm begins with the 250 SX-F. The 2020 version is once again set to dominate motocross tracks. Not content with being one of the lightest in its class, it offers unrivalled, yet perfectly controllable, power delivery. That's why it appeals to amateurs and professionals alike. The secret of a good motor is its ability to handle power with maximum efficiency. This package is a real winner in this respect, and will have no trouble taking you to victory.

engine and silencer

4-stroke engines have revolutionized motocross and established KTM as a major player in the sport. Incredibly light and compact, these little engineering gems impress with their power and dynamism. right out of the dealership, KTM 4-strokes let you experience the highest level, in the purest READY TO RACE spirit.

engine

renowned as one of the most powerful engines in the MX2 class, the 2020 version continues to assert its dominance. The engine block's compact architecture allows better mass centralization and ensures impeccable handling. The 2020 model's reliability has been further enhanced by various improvements and a new, more robust oil pump intermediate gear. Powered by a compact, powerful and lightweight engine (just 25.9 kg), the 250 SX-F is a force to be reckoned with. It's nonetheless easy to master, to the delight of amateur and professional riders alike.

cylinder head

the centerpiece of the compact DOHC (double overhead camshaft) engine, the avant-garde cylinder head features two overhead camshafts responsible for the action of a single camshaft. titanium valves (32.5 mm intake, 26.5 mm exhaust) using ultra-light, DLC-coated rockers. Camshafts feature an ultra-fine surface to minimize friction. The valve train has been designed to optimize power delivery.

crankshaft

the 250 SX-F's crankshaft is particularly rigid. The connecting-rod bearing features two bearing shells press-fitted directly into the crankpin. This type of design is essential to support the extremely high rotational speeds of the 250 cm3 4-stroke engine. It also increases engine life and extends crankshaft service intervals, a crucial advantage in terms of time, effort and cost.

crankcases and covers

the use of a high-pressure die-casting process results in a relatively compact crankcase that is even lighter, while maintaining its strength and durability. The design of the crankcase has enabled KTM engineers to move the shaft mountings closer to the center of gravity, so as to better centralize the masses and enhance rideability. Another interesting innovation to keep the engine as radiant as in the early days: crankcase covers with an elaborate surface structure, designed to reduce wear caused by the rider's boots.

gearbox

the 250 SX-F features a robust 5-speed gearbox. The gear ratios of the previous version, perfectly suited to motocross riding, have been retained. Another highlight of the transmission is the "zero dirt" design of the selector. Designed on the same principle as the footrest, it prevents the accumulation of dust and enables the gearbox to remain operational in all conditions.

engine management

the highly sophisticated Keihin engine management system, with electronic fuel injection, features a 44 mm injector body. The position of the injector ensures excellent atomization of the fuel and air entering the combustion chamber. The engine is even more lively and generous when the throttle is opened. You also have independent control systems for cold start and idle. The engine control unit (ECU) offers specially adapted exhaust and cylinder head mappings to better manage traction and start-up control. To deliver maximum power, the ECU adapts the engine's characteristics at each speed, according to the data communicated by the gear sensor.

cylinder and piston

the 78 mm-bore cylinder houses a forged bridge-box piston of the highest quality, manufactured by CP. In addition to its extremely rigid structure, it features a unique crown shape to match the high level of compression in the combustion chamber. The high compression ratio (14.4:1) and reduced oscillating masses give the engine an extremely responsive character.

balancer shaft

to compensate for the inertia generated by the 250 SX-F, the engine is fitted with a multifunction balancer shaft. In addition to its beneficial effect on vibration levels, this shaft also drives the timing chain and water pump.

clutch

the DS (Diaphragm Steel) clutch transfers control to the rider's hands. It consists of a durable one-piece clutch housing and a main gear (made of ultra-high-strength billet steel), offering rock-solid reliability. Extremely heat-resistant steel motor friction discs are preloaded by a diaphragm spring to optimize clutch release. This type of design significantly reduces the force exerted on the clutch, even more so with the Brembo hydraulic system.

electric starter

every minute is precious in racing. The electric starter allows you to get back into the race without wasting time. The electric starter, standard on the 250 SX-F, uses MITSUBA's robust electric motor. The rock-solid reliability of this device saves precious starting time at crucial moments in the race.

handlebar map selector

all 4-stroke models feature a handlebar-mounted map selector.all four-stroke models feature a handlebar-mounted map selector for traction and start control, and for switching between power curves (Standard Advanced). Traction control is designed to enhance traction and control during acceleration, especially on demanding tracks. This function can be activated, even at full throttle, by means of the map selector on the handlebars. When the engine is idling, simply press both switches at the same time to activate Start Control, and you'll be off the grid even faster. In addition to the standard engine modes, the map selector gives access to other engine modes for maximum racing options.

cooling

to ensure smooth power delivery, it's essential to maintain optimum engine temperature. The position of the 250 SX-F's radiators, perfectly matched to the design of the spoilers, lowers the center of gravity and enhances ergonomics. Thanks to CFD (Computational Fluid Dynamics) and a judicious cooling circuit, this innovative system ensures that engine components are kept at the ideal temperature to guarantee the highest level of performance, whatever the conditions. Special radiator guards not only protect the radiators from stones and other debris, but also distribute the force of impact around them.

muffler

the exhaust system, fitted to all 4-stroke models, gives the engine a smoothness and liveliness that are hard to match. It features an exhaust manifold (specific to each model) and a small additional chamber, i.e. an advanced resonator known as the FDH (Flow Design Header) or flow-design exhaust manifold. This design allows the exhaust to be disassembled without removing the shock absorber, and facilitates access to the latter. The aluminum sleeve, the muffler tip and the internal structure of the muffler offer a further ergonomic advantage, slimming the silhouette of the motorcycle while complying with regulatory noise emission levels.

chassis

the better the motorcycle feels, the better and more intense the adventure is likely to be. The chassis plays a vital role in the bike's road feel. The 250 SX-F relies on a lightweight, high-tech steel frame capable not only of mitigating the effects of the many irregularities of motocross terrain, but also of providing excellent feedback to the rider. Suspension damping characteristics have been optimized on the 2020 version. In particular, the suspension settings have been revised to provide even greater suppleness and comfort. Combined with a highly flexible chassis, these suspensions make the riding experience more intuitive and enjoyable than ever.

frame

the frame of the 250 SX-F favors the dynamic riding styles that are de rigueur in this class. As with the rest of the KTM SX range, the frame is made of hydroformed chromium-molybdenum steel tubes, assembled by automated welding to guarantee the highest levels of quality. Rigidity has been designed to enhance handling. The excellent cohesion with the suspension offers the perfect compromise between agility and high-speed stability. The frame of all KTM SX 2020 models benefits from a highly resistant lacquered coating and standard frame protectors. The lightweight aluminum rear buckle provides excellent feel for the rider and promotes mobility in the saddle.

swingarm

the 250 SX-F's one-piece, high-pressure-molded swingarm has been designed for maximum strength and minimum weight. It offers a wide range of rear-wheel adjustments, allowing you to shorten the wheelbase for greater manoeuvrability on narrow, winding tracks or, on the contrary, to increase the wheelbase for greater stability on fast sections. The chain measurement marks on the swingarm are visible from above, making adjustments much easier.

wheels

featuring ultra-light CNC-machined hubs and top-of-the-range Excel rims, the wheels on all SX models guarantee maximum stability despite limited weight. The aluminum spoke nipples have been redesigned to reduce the frequency with which spokes need to be re-tensioned. The wheels are fitted with latest-generation DUNLOP Geomax MX 3S tires, to maximize power transfer to the ground and enhance stability.

front suspension

all standard-size KTM SX models feature the ultra-light WP XACT AER fork, with new settings for the 2020 model year. The arms of this 48 mm USD air fork have different functions: damping is on the right, air springing is on the left. The left fork arm features a double-chamber air cartridge system designed to prevent any loss of pressure. Should the outer seal leak, the pressure exerted inside the inner cartridge will keep the bike in its normal position. The air spring is extremely easy to adjust, and can be adapted to the rider's weight using a single valve and the air pump supplied with the bike. The right fork arm features a cartridge specially designed to meet the requirements of the single-arm design, and can be adjusted to suit track conditions or rider preference. To fine-tune each of these settings (compression from the top and rebound from the bottom), simply turn the new 30-notch knob above each fork arm.

rear suspension

the WP XACT DDC shock absorber, featured on all KTM SX models, has beenthe WP XACT DDC shock absorber, found on all KTM SX models, was developed with the frame and swingarm architecture in mind, as were the linkage system and the WP XACT AER fork. Beyond its purely functional aspect, this little jewel captivates with its meticulous attention to detail, and in particular its high-quality machined and anodized components. Fully adjustable for high-speed and low-speed compression, it can be specifically adapted to track conditions or rider preferences.

fork tees

all KTM SX models use high-quality CNC-machined fork crowns, a KTM trademark. To take account of the flexibility of the frame and fork, engineers have stiffened the upper fork crown (22 mm offset on all models). The front end works in perfect harmony with the frame, making the bike even more stable and agile. Two positions are possible for the handlebar trigger guard, with vibration-damping pads. The hour meter, fitted as standard on the upper fork crown of all SX models, keeps track of hours spent in the saddle and indicates when it's time for maintenance.

brakes

state-of-the-art Brembo brakes are standard equipment on KTM motocross bikes. Combined with Wave brake discs renowned for their lightness, they deliver the stopping power expected by the most daring riders.

fuel tank

all KTM SX models feature an ultra-light polyethylene fuel tank. The shape of this tank has been designed to be more ergonomic, while retaining the same capacity (7 liters). The internally threaded fuel filler cap ensures easy, reliable closure.

air filter housing

the air filter housing of the 250 SX-F has been completely redesigned to optimize flow dynamics. Combined with the new intake snorkels, it ensures exceptional power delivery and acceleration. In addition to the obvious performance gains, the new design also protects the air filter from clogging. The rigid support for the large Twin-Air filter has been designed to minimize installation errors. As on previous models, the filter can be serviced in record time and without tools, a typically KTM feature.

ergonomics and comfort

the stronger the bond between rider and bike, the more spontaneous and natural the rider's movements, and the more dynamic the bike. To ensure flawless ergonomics and optimum performance on the 2020 range, KTM engineers have ensured that the rider can adopt an ideal position on the bike, for improved handling. What's more, the handlebar position can be adjusted to suit the rider's preferences and build. As the rider interacts primarily with the fairing, seat, footrests and handlebars, these points of contact are crucial to maintaining total control of the vehicle. KTM has made no compromises on ergonomics, and has consistently opted for the highest quality components on all KTM SX 2020 models.

saddle

the saddle on all KTM SX models confirms the progress made in terms of dynamics and ergonomics. The saddle cover incorporates silicone strips to optimize grip and feel. A long screw inserted into the side of the saddle secures it more securely to the motorcycle, making it easier and safer to handle.

handlebars

all standard-size KTM SX models feature the same ultra-strong, profiled aluminum handlebars made by NEKEN. Two positions are possible for the handlebar trigger guard with shock absorbers. right: an ODI vulcanized grip available as standard; left: an ODI lock-on grip that's as comfortable as it is practical, thanks to its glue- and wire-free mounting system.

footrests

sophisticated "zero-dirt" footrests prevent the pivot from fouling, even when driving through deep ruts. Riding position not high enough? No problem! The footrest mounting system on EXC models since model year 2019 has been raised by 6 mm compared to that of SX versions.

styling and graphics

kTM 4-stroke motocross bikes are the market benchmark for innovation and style. The result of a joint effort by KTM factory riders, KTM R&D specialists and design agency Kiska GmbH, the fairing of the 250 SX-F marks a new stage in the evolution of motorcycles, both stylistically and functionally. The shape of the fairing allows the rider to feel at one with the machine. The main focus has been on contact points, to ensure total freedom of movement for the rider and enhanced handling. The special shape of the front and rear shells ensures maximum stability and minimum weight.

decals

the new overmolded decal kit reinforces the bike's aggressive look and confirms the ambitions of the KTM brand.

software and electronics

4-strokes marked a turning point in the motocross era. The SX-F motorcycle range enabled KTM to push the boundaries of performance innovation. To stay one step ahead of its rivals in the MX2 class, KTM has equipped the 250 SX-F with a handlebar-mapping selector. This activates innovative functions such as traction and start control, and can even be used to change the power curve. Absolute performance requires state-of-the-art electronics to transfer maximum power to the ground. KTM SX-F models also benefit from unique advantages such as the proven electric starter. A simple push of a button is all it takes to switch to READY TO RACE mode.

battery

To start the engine every time, especially in cold weather, the starter on SX-F models is powered by an ultra-light, high-performance 2 Ah lithium-ion battery. The voltage regulator and capacitor, as well as all electrical components, are housed under the saddle for maximum reliability and compactness.

traction control

this extremely practical function ensures more efficient traction and better control of the bike during acceleration on wet or slippery surfaces. It can be activated, even in full throttle, by means of the map selector on the handlebars.

control at the start

simply press both map selector switches at the same time to activate START CONTROL and accelerate off the starting grid. Start Control reduces the engine's maximum speed at the precise moment of take-off, so you can maintain better control of your machine. The EFI light mounted on the upper fork tees flashes when this function is active.

handlebar-mounted map selector

at the touch of a button, the map selector switches between a standard engine mode and a more aggressive engine mode for trails with good grip. This allows the rider to better adapt the bike's handling to track conditions, or to benefit from better control when starting to show signs of fatigue.

Information and images credits: KTM