Motorcycle specifications KTM450 SX-F 2018 Dominating Supercross

Lightning-fast, the KTM 450 SX-F wants to reach seventh heaven. Thanks to its compact engine, which delivers explosive yet controllable power, it is the weapon of choice for the official Red Bull KTM Racing factory team and its champion, Ryan Dungey. This READY TO RACE bike rules the AMA Supercross Championship circuits. Its secret? Devilish agility and firepower.

fRAME

the high-tech chromium-molybdenum steel frame is a model of lightness, flexibility and handling, offering excellent stability and diabolical precision in the 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 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.

wEIGHT

year after year, KTM engineers strive to make their bikes lighter. The result is clear: the 2018 KTM SX models are among the lightest and sleekest motocross bikes on the market. The 4-strokes are equipped as standard with a highly beneficial electric starter, whereas competing models still have to be kick-started.

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 has been raised by 6 mm compared to the 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 the filter can be replaced even with a muddy face. And without the need for any tools. And in a matter of seconds.

eXHAUST SYSTEM

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.

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 7.0 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

eNGINE

with its much more compact dimensions, superior performance across the entire rev range and significant weight savings, the 450 SX-F's engine is a resounding success. Recognized as one of the lightest 450s on the motocross market, it is nonetheless a true racing beast. equipped with a single overhead camshaft cylinder head and the latest electronic fuel injection system, it boasts an unrivalled 62 hp. Engineers have redoubled their efforts and ingenuity to extend service intervals and opt for state-of-the-art engine management, to the delight of enthusiasts and professionals in search of new records.

cRANKSHAFT

in the SOHC cylinder head, the overhead camshaft drives four ultra-light titanium valves via ultra-rigid rockers coated with DLC on the intake side. A configuration such as this enables a rotational speed of 11,500 rpm, no mean feat for a large-displacement engine like this. Aluminium side brackets have been added to secure the engine to the frame and lighten it by a few extra grams.

cYLINDER AND PISTON

the shortened cylinder, with a 95 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, features a rigid structure and reduced weight. The reduced oscillating masses give the engine its playful, muscular character.

cRANKSHAFT

the crankshaft of the KTM 450 SX-F uses a shortened connecting rod. More compact and lighter, the engine also gains in responsiveness. The crankshaft is fitted with a connecting-rod head 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.

eNGINE MANAGEMENT SYSTEM

the Keihin electronic injection engine management system features a 44 mm throttle valve 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 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 power curve knob, even enhances the aggressive character of your machine.

eNGINE 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.

gEARBOX

the new engine of the KTM 450 SX-F uses an ultra-light 5-speed gearbox that offers the same ratios as the previous model.same ratios as the previous model, perfectly matched to the power delivered by the large-displacement engine. What's more, the 1st and 3rd gears now feature a special surface treatment for greater reliability. The "zero dirt" design of the selector avoids clogging and jamming of the lever joint, for safer gear changes. All 4-stroke engines are equipped with an engaged-gear sensor to adapt engine characteristics to each gear. On the AM18, the gearbox shaft features a stronger selector star and a C4 bearing with greater radial clearance. This enhances reliability, even under extreme operating conditions.

bALANCING SHAFT

the side-mounted balancer shaft also drives the water pump. Thanks to perfect mass balancing and reduced oscillating masses, engine vibration is reduced to a minimum, even when the SX-F is running at full speed.

eLECTRIC STARTER

the KTM 450 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.

eMBRAYAGE

the KTM 450 SX-F uses a DDS (Damped Diaphragm 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. A special feature of this clever design is the use of a diaphragm spring instead of the usual coil springs, giving the clutch greater flexibility. The diaphragm spring also leaves plenty of room for a damping system integrated into the clutch hub, to enhance traction and durability. The clutch is activated by a hydraulic system manufactured by Brembo, which plays an essential role in the clutch's progressiveness and flexibility.

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 of the spoilers, these radiator guards are particularly useful in the event of an impact.

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 features new tuning and a softer spring to match the new front-end setting. As always, the shock absorber comes in WP's trademark gleaming colors.

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 air fork pump supplied as standard 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.

bRAKES

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.

eLECTRIC STARTER

like all KTM 4-stroke motorcycles, the 450 SX-F starts at the touch of a button, an undeniable advantage when it comes to setting a new lap time.

hANDLEBAR-MOUNTED POWER CURVE CHANGE BUTTON

all 4-stroke models feature a new handlebar-mounted power curve switch that fulfils 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 principle is simple: the start control reduces the engine's maximum speed at the precise moment when you start, to 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 warn you that your bike is in READY TO RACE mode. In addition to the standard engine maps, there's another, even more powerful engine mode.

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 do-it-yourselfers will appreciate this.

gRAPHICS

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

cARENAGE

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.

Information and images: KTM