DYNAMIC IN EVERY WAY
The KTM 250 SX-F was primed for global domination and is set to continue its dominance with more innovative changes. Not only is it the lightest bike in its class, but it also offers unrivalled, confidence-inspiring power delivery, making it a great choice for both amateur and professional riders. Laying the power down effectively is the secret to fast lap times and this capable package has all the right credentials to get the most important job done - getting to the chequered flag first.
ENGINE & EXHAUST
As power is relative to weight, KTM engineers have worked tirelessly to produce an engine with class-leading power and the lowest weight in the MX2 category. The end result is a motorcycle that sets the class benchmark for power-to-weight ratio and is the strongest in MX2 competition. With many updates, including valve timing, exhaust, airbox and EMS (engine management system), the power unit produces more torque and power across the entire rev range than ever before. Its compact architecture contributes to excellent mass centralization, which supports the easy rideability of the bike. In short, the combination of a compact engine layout and unrivalled power makes the new KTM 250 SX-F an undisputed winner once again.
Renowned as the strongest engine in MX2 competition, the 2019 version pushes the boundaries of innovation even further. With updates on valve timing, exhaust, airbox and EMS, the entire power pack produces even more torque and power across the entire 14,000 rpm range. Its compact structure contributes to excellent mass centralization, which supports the easy ride-ability of the bike. The low weight of only 25.9 kg, in combination with the compact engine layout and unrivalled power, once again makes the new KTM 250 SX-F a real force to be reckoned with, yet still easy to ride for both amateur and professional riders.
An integral part of the class-leading power delivery is the cutting-edge DOHC (double overhead camshaft) cylinder head. It features two overhead camshafts which activate the titanium valves (intake 32.5 mm, exhaust 26.5 mm) via the super-light, DLC coated finger followers. For 2019, the exhaust camshaft features a new timing that has further refined power delivery.
The 250 SX-F's has a rigid crankshaft which features a connecting rod with a plain big end bearing featuring two force-fitted bearing shells run directly on the crank pin. This design is a major prerequisite for the extremely high engine speed levels and the unrivalled maximum power of the 250cc engine. Not only that, it enhances the engine's durability, allowing long crankshaft service intervals, which is a huge customer benefit in relation to time, effort and cost.
CRANKCASES AND ENGINE COVERS
The compact engine cases are manufactured using a high pressure die-cast production process that helps with weight reduction, while retaining strength and durability. The design allows for optimal shaft arrangements close to the center of gravity, resulting in ideal mass centralization and easier ride-ability. Plus, the new engine covers feature a smart surface structure that reduces wear caused by the rider's boots, keeping them looking as fresh as the day you bought it.
The KTM 250 SX-F is now fitted with a new, more robust 5-speed transmission. The gear ratios were carried over from the predecessor, but all the gears feature improvements and reinforcements. Another highlight of the transmission is the no dirt gear shifter. Similar to the foot peg design, it prevents the build-up of dirt and ensures the next gear is always available, no matter what the conditions.
ENGINE MANAGEMENT SYSTEM
The state-of-the-art Keihin Engine Management System, with electronic fuel injection, features a new 44 mm throttle body. The injector position is unique and guarantees optimal atomization of the fuel and air on the way to the combustion chamber, resulting in instant response and maximum performance when opening the throttle. There are also separate systems for cold starting and idle adjustment, while an improved seal of the MAP sensor (MAP = Manifold-Absolute-Pressure) makes the system even more reliable. A reworked throttle cable mount allows for easy access and smoother routing of the cables. Additionally, for 2019, the ECU features new maps which have been adapted to the new exhaust and cylinder head, regulating traction and launch control. It also provides different maps for each gear, according to the information received from the gear sensor, ensuring maximum power as you shift through the gears.
In order to balance the mass-forces the 250 SX-F produces, the engine is fitted with a multifunctional counter balance shaft. It effectively reduces vibration and drives the water pump and timing chain.
CYLINDER AND PISTON
The 78 mm bore cylinder houses a lightweight, forged, bridged, box-type piston, made to the highest standards by CP. It has an extremely rigid structure and features a unique crown shape to suit the high-compression combustion chamber. The compression ratio is at 14.4:1 and thanks to the combination of low oscillating masses, the engine displays extremely lively characteristics.
Time is crucial in the heat of the race and an electric starter gets you fired up and back in the battle as soon as possible. The electric starter is standard on the KTM 250 SX-F and features a strong starter motor made by Mitsuba. The proven starter drive guarantees efficient and reliable starting when you need it most.
HANDLEBAR MAP SELECT SWITCH
Within easy reach of the left grip on all four-stroke models, is a multi-functional handlebar map switch, which features the innovative control functions, traction control, launch control and alternative power curves (standard <-> advanced). The TRACTION CONTROL is a unique feature which has a new setting for 2019. It guarantees more efficient traction and better control when accelerating the bike, especially in challenging track conditions. It can be activated on the handlebar map switch while riding. With a simple push of the two buttons at idle speed, the rider can also activate LAUNCH CONTROL, ensuring the most effective launch out of the gate. Thanks to a reworked set-up, the Launch Control now benefits from directly from the Traction Control, reducing wheel spin for maximum possible traction. The map switch also gives the rider the chance to select an alternative power map, besides the standard configuration, providing him with options during the race.
Maintaining the optimal engine temperature is crucial to ensuring consistent horsepower throughout the ride. The KTM 250 SX-F features newly designed radiators which are mounted 12 mm lower than the predecessors. This lowers the center of gravity and matches the design of the new shrouds perfectly, in order to achieve perfect ergonomics. By using CFD technology (computational fluid dynamics) together with a clever coolant circuit routing, the innovative system ensures the optimum engine temperature for the highest performance, no matter what the conditions. The radiators also feature special protectors that don't only serve as protection from flying rocks and debris but also as a brace that disperses energy around the radiators in the event of an impact.
When it comes to improved power delivery and performance, the new exhaust on all 4-stroke models play a key role and packs a punch that is hard to beat. It features a new, model specific header pipe with a further advanced resonator called FDH (Flow Design Header), which is a small chamber around the pipe. The silencer has a new profile aluminium sleeve and a new end cap, as well as a reworked internal design. The new shape allows the exhaust to be disassembled without removing the shock absorber and also provides better access to the shock. Another benefit of the new shape is slimmer ergonomics, making the bike feel narrower, without compromise to regulatory noise limits.
Every rider knows that when the feeling on the bike is good, the ride is awesome. The chassis forms an integral part of this "feeling" and has been designed to provide accurate feedback between track and rider, while also reducing the harshness of typical motocross terrain. The KTM 250 SX-F features a new lightweight, high-tech steel frame that not only provides a great feeling, but has been optimized for more accurate rider feedback. The new flex characteristics provide excellent agility and high-speed stability, contributing to an intuitive ride like no other.
The new frame on the KTM 250 SX-F has to cater for the dynamic riding styles associated with MX2 racing. For this reason, along with the rest of the SX range, it is professionally crafted from hydro formed Chromium Molybdenum steel tubes that are robot welded, ensuring the highest levels of consistent quality. Improved stiffness equals more responsive handling, while the frame works in even better with the WP suspension, to ensure excellent agility and high-speed stability. The frame features "no-dirt" footpegs with a simple but effective self-cleaning system that let the footpegs return to their original position every time, for complete control in all conditions. On all the 4-stroke frames, there are three new mounts that allow an optional composite skid plate from the KTM PowerParts program to be fitted. All 2019 SX frames feature a highly durable powder coating, just like the KTM Factory machines, and come with standard frame protectors. The 40 mm longer new subframe is made from lightweight aluminium, for improved movement across the seat and heightened rear fender stability.
The KTM 250 SX-F's new one-piece swingarm, is manufactured with a gravity die-cast production process, for exceptional strength at the lowest possible weight. It also has a 5 mm longer axle slot, allowing the wheel to be adjusted further back, for even greater stability on choppy tracks. The swingarm's chain measurement markings are visible from above, making adjustment simpler and more accurate.
KTM uses lightweight, CNC-machined hubs and high-end Excel rims on all SX models, guaranteeing maximum stability and minimum weight. For 2019, the aluminum spoke nipples feature a reworked design, which conveniently reduces the frequency with which the spokes need to be tightened. The wheels are fitted with the latest Dunlop Geomax MX 3S tires, delivering maximum grip and stability and effectively transferring all the power to the ground.
All full-size SX models are fitted with the super-lightweight WP AER 48 front fork. It is a 48 mm USD air-sprung fork with separate functions for each fork leg, meaning damping functions are on the right side and the air spring is on the left. The left leg features a two-chamber system with a capsuled air cartridge, helping prevent loss of air pressure. Essentially, this means that in the rare case of a leaking outer seal, the internal cartridge pressure keeps the bike in a normal position. The air spring is exceptionally easy to use and can be adjusted to any rider weight via a single air valve and the air pump that is supplied with the bike. The right fork leg integrates a damping cartridge to fit single damping leg requirements and can be adjusted to the track conditions and the rider's preferences. (compression from top, rebound from bottom, 30 clicks each). For 2019, new settings on the damping side have improved the damping characteristics, providing great front end feel and control.
All SX models feature a DDC monoshock, which has been developed to work as a complete unit with the entire frame and swingarm architecture, as well as the linkage system and the AER 48 forks. It features high-quality machined and anodized components, which add a touch of class and give it appeal beyond just a functional necessity. Internally, the shock houses an updated main piston and new settings that provide improved damping characteristics, perfectly complimenting to the reworked front-end setup. It is fully adjustable, including high and low speed compression, allowing you to set the shock up precisely to suit any track and rider's preferences.
All SX models feature top quality, CNC-machined triple clamps and have become somewhat of a KTM trademark. For 2019, the triple clamp has been reworked with stiffer upper clamps (22 mm offset for all models) to suit the reworked frame stiffness and flex characteristics of the latest WP AER forks. The result is a front end that works in perfect harmony with the frame, improving overall handling and stability. The rubber damped handlebar fixation reduces vibration and also allows for some adjustment with 2 different mounting positions. An hour meter is fitted as standard on the upper triple clamp on all SX models, keeping the rider informed of the number of hours spent tearing up the track and when the next service is due.
High-tech Brembo brakes have always been standard equipment on all KTM motocross bikes. Combined with lightweight wave discs, the renowned system provides the highest level of braking efficiency, enabling you to out-brake the competition.
All models in the SX range are fitted with newly designed lightweight polyethylene fuel tanks. The fuel capacity on the full-size SX models is still 7 liters, but the new shape improves the ergonomics. The filler cap has an inside thread that makes for easy and reliable closure. For the 4-stroke models the fuel pump assembly features optimized internal routing of the hoses for improved reliability.
The new airbox on the KTM 250 SX-F has been completely reworked to ensure better flow dynamics, and together with new intake snorkels, leads to optimal power and throttle response. Despite the obvious performance enhancements, the new design also offers maximum protection against soiling of the air filter. The large Twin-Air air filter is mounted on a cleverly designed stiff cage that minimizes incorrect installation. As found on previous models, filter maintenance is quick and easy and does not require tools - a standard, original feature from KTM.
ERGONOMICS & COMFORT
It is important for a rider to work in harmony with the motorcycle, maintaining momentum by moving together with the natural forces. KTM has focused extensively on ergonomics that are optimal for high-level performance, ensuring a neutral riding position that offers the best maneuverability and control. The handlebar position can also be adjusted to suit every rider size and ergonomic preference. A rider's main interaction with the motorcycle comes through the bodywork, seat, footpegs and handlebars, which all play a vital role in overall control. When it comes to ergonomics, absolutely no compromises were made and only the best quality products feature on the 2019 SX models.
All SX models have a newly shaped seat, designed to match the improved ergonomics. The seat cover features newly developed silicone strips that provide better feel and grip for the rider. The seat is conveniently fixed to the bike using one long, lateral screw, making it safe and easy to handle.
All full-size SX models are equipped with the same high-strength aluminum tapered handlebar, made by NEKEN. The handlebar is fixed in rubber damped mountings, which allow for two different positions. The handlebars come standard with an ODI vulcanized grip on the right side and a comfortable ODI lock-on grip, which does not require any wire or glue, on the left. They also feature a reworked bar-pad with a newly designed cover that can be attached and removed a lot quicker and easier. With these handlebars, the control needed to win races, lies comfortably in the rider's hands.
Sophisticated 'No Dirt' footpegs prevent clogging of the footpeg pivot, even when digging in deep ruts. Looking for a higher riding position? Then just mount the footpegs of the MY2018 EXC models, which are 6mm higher than the SX versions
BODYWORK & GRAPHICS
KTM's 4-stroke motocross bikes are the industry benchmark when it comes to innovative technology and styling. With input from KTM's factory riders, as well as KTM R&D and Kiska Design, the new bodywork of the KTM 250 SX-F pushes the boundaries of progression even further. The result is a shape that achieves complete harmony between rider and bike and features across the entire SX range. The main goal was to provide the optimal contact points that allow a rider maximum freedom of movement and improved handling. The front and rear fenders feature an intelligent I-beam design, guaranteeing maximum stability with the lowest possible weight. The new graphics add to the fast and aggressive style of the bike and also confirms KTM's never-ending quest for race-winning progression.
A new, tailor-made kit and a Factory orange frame. Because in this sport, champs deserve to look the part regardless of the dirt.
SOFTWARE & ELECTRONICS
4-strokes have defined the modern era of motocross and KTM have used the SX-F range to push the boundaries of innovation. To stay ahead in the competitive MX2 class, KTM equipped the 250 SX-F with a multifunctional handlebar map switch. The unit activates innovative features like traction control, launch control and even alternative power curves. KTM's engineers have pushed performance to the extreme, making electronics a necessary progression that ensures power is delivered in the most effective way. KTM SX-F models also feature other unique advantages, like the proven electric starter. Now, more than ever, READY TO RACE performance is just the push of a button away.
BATTERY & WIRING HARNESS
All SX-F models feature a new, more capable, super lightweight 2 Ah Lithium-Ion starter battery, ensuring even safer starting of the engine, especially in cold weather conditions. The packaging of the voltage regulator and condenser has been reworked to concentrate all the electrical components in a common area below the seat, making the entire system even more reliable.
1-cylinder, 4-stroke engine
Wet multi-disc clutch, hydraulically actuated
25CrMo4 steel central-tube frame
WP-USD, AER 48, Ø 48 mm
WP shock absorber with linkage
Suspension travel (front)
Suspension travel (rear)
Front brake disc diameter
Rear brake disc diameter
5/8 x 1/4"
Steering head angle
Tank capacity (approx.)
Weight READY TO RACE (without fuel)
The illustrated vehicles may vary in selected details from the production models and some illustrations feature optional equipment available at additional cost.
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