Motorcycle specifications KTM450 SX-F 2016 The cross weapon

When maximum power is required, there's no other choice than the 450 SX-F. This model has proved its worth over the years in the world's leading championships. Thanks to its compact SOHC (single overhead camshaft) engine, which delivers explosive yet controllable power, it is the weapon of choice for the official KTM US factory team and Ryan Dungey, winner of the 2015 AMA Supercross Championship.

engine

With new features including significantly more compact dimensions, improved performance across the rev range and a weight saving of 1.8 kg, this new engine is the lightest 450 on the motocross market. Equipped with a redesigned single overhead camshaft cylinder head and the latest electronic fuel injection system, it boasts an unrivalled power output of over 62 hp and extremely efficient power delivery.

cylinder head

Inside the new cylinder head, which features an improved water jacket and combustion chamber, fuel flow through optimized ports is controlled by a new overhead camshaft. It drives four ultra-light titanium valves through ultra-rigid rocker arms coated with DLC on the intake side. This configuration enables engine speeds of up to 11,500 rpm. Thanks to its compact design, the cylinder head is 350g lighter than the previous model.

cylinder and piston

The improved cylinder, shortened by 6 mm, with an optimized water jacket and 95 mm bore, houses an ultra-light box-in-box piston and a lightened piston pin, which contribute significantly to the engine's low vibration and high revs. Compression is 12.6:1.

crankshaft

The 450 SX-F's crankshaft is 10% more inertial (with no increase in weight) and uses a shorter connecting rod than the previous model, contributing to the engine's compactness, lightness and responsive character. A higher balancing factor reduces vibration levels. The connecting-rod bearing features two force-mounted half-bearings acting directly on the crankpin, and the oil supply is provided by the engine's pressure lubrication circuit. This general concept offers customers longer intervals between overhauls.

balancing shaft

To balance mass forces, the new 350 SX-F engine uses a multifunctional balancer shaft that simultaneously drives the water pump and timing chain. It is fitted with new sprockets mounted on the new timing chain.

electric starter

Like all KTM four-stroke motorcycles, the 450 SX-F can be started at the touch of a button. The use of an electric starter has proved to be a considerable advantage time and again, particularly in competition.

crankcase and cover

The entirely new design of molded crankcases offers a much more centralized shaft configuration, allowing the crankshaft to be raised by 7 mm and moved back 9 mm closer to the motorcycle's center of gravity - a weight reduction of 550 g for a final weight of 27.3 kg (EU) and 27.8 kg (USA). The new magnesium engine covers feature an advanced surface structure to reduce wear caused by the rider's boots.

engine management system

The completely redesigned Keihin electronic fuel injection engine management system features a new 44 mm throttle body for spontaneous response and maximum performance, thanks to a revolutionary injector position. The new ECU (Engine Control Unit) includes a start-up control function to improve starting efficiency, and provides different configurations depending on which gear switch is selected. Using the handlebar-mounted selector, the rider can also activate an optional configuration for a different power curve.

clutch

The 450 SX-F uses a DDS (Damped Diaphragm Steel) clutch developed by KTM, featuring a wear-free steel bell and heat-resistant clutch plates. A special feature of this design is the use of a diaphragm spring instead of the usual coil springs, giving the clutch greater flexibility. The diaphragm spring also leaves ample room for a damping system integrated into the clutch hub, offering improved traction and longevity.

gearbox

The new 450 SX-F engine uses an ultra-light 4-speed gearbox offering the same ratios as the previous model, perfectly matched to the power delivered by the larger-displacement engine. In addition, the 1st and 3rd gears now receive a special surface treatment for greater reliability. For the American market, the 450 SX-F comes with a 5-speed gearbox to meet the demands of American customers who use the bikes on faster circuits and for desert outings.

lighter weight

The main objective of KTM's engineers in developing the new-generation SX was to significantly lighten the weight and improve handling. With a weight reduction of between 4 and 5 kg, the result is exceptional, making the new KTM models the lightest motorcycles on the market, despite the fact that the four-stroke models are fitted as standard with a highly beneficial electric starter, whereas competing models have to be kick-started.

fork

The new KTM SX models are equipped with a revolutionary new ultra-light WP fork, a 48 mm inverted air-sprung fork developed by WP Suspension in close collaboration with KTM. This is a split fork with separate functions for each fork arm. The damping functions are on the right, the air spring on the left. The left fork arm houses an air cartridge. The air spring is easily adjusted to the rider's weight using a single valve and a standard fork air pump. The right fork arm features a new cartridge specially designed to meet the requirements of the single-arm design, and damping can be adjusted to suit track conditions or rider preference with a simple turn of a knob. With a travel of around 300 mm, the new fork offers exceptional response and excellent, consistent damping characteristics. It is also 1.4 kg lighter than the previous model.

fork crown

High-quality CNC-machined fork crowns have been a KTM trademark for many years. Enabling precise steering, they significantly enhance the flexibility characteristics and, thus, the action of the fork. For 2016, the upper fork tee features a new rubber damping system for the handlebar clamp to reduce the level of handlebar vibration. The fork tees retain front-to-rear adjustability according to rider preference.

monoshock

The new generation of monoshocks manufactured by WP Suspension has been designed for the new SX models, in conjunction with the new frame and swingarm architecture, modified linkage and new WP fork. The linkage system has also been reworked, with modified geometry and extended tie-rods, and was tested last season on most KTM factory bikes.

air box

The new airbox design offers optimum protection of the air filter against clogging and maximum airflow. The new intake snorkels are 300g lighter and made from a new, performance-enhancing material that reduces deformation caused by air intake pulses. As on previous models, the new double air filter is easy and safe to fit, and can be changed in seconds without tools - an original KTM standard feature.

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. For 2016, the SX-F range has succeeded in integrating an ultra-light and compact lithium-ion starter battery weighing 495 g on a standard motocross bike, enabling safe starting and a weight saving of 1 kg compared to 2015!

brakes

High-tech Brembo brakes have always been standard equipment on KTM off-road bikes. They are combined with redesigned, lightened wave-type discs with improved thermal resistance manufactured by GALFER. The ultimate solution in braking technology. 63g lighter at the front, 32g lighter at the rear.

wheels

The 450 SX-F is equipped with ultra-light CNC-machined hubs, top-of-the-range Excel rims, new lightened spokes and aluminum spoke-heads for maximum stability and minimum weight. Dunlop's new MX tires (Geomax MX 32) have been developed with the KTM racing team in the USA on the basis of factory tests and the racing experience of seasoned riders. They guarantee perfect traction and exceptional performance.

frame

The new frame design offers around 20% more torsional stiffness, around 30% less longitudinal stiffness, and features redesigned engine mounting lugs to reduce vibration. This increased flexibility enables better absorption of the energy generated by front and rear wheel loads, supporting the suspension for greater comfort and reduced rider fatigue. A 0.4° greater steering angle and a 10 mm shorter wheelbase contribute to improved handling, as does a 380 g lighter weight than the previous model.

footrests

A new "zero-dirt" footrest design prevents dirt from blocking the footrests when they are returned to position, even in deep ruts. The new footrests are also wider and more stable, offer better grip and are lighter than on previous models.

swingarm

As on previous models, the new generation SX is equipped with a new cast aluminum swingarm. The new one-piece cast swingarm offers reduced weight and optimized bending behavior for enhanced damping characteristics. The weight saving is 250 g.

cladding

For the new generation of SX models, KTM factory riders collaborated with KTM R&D specialists and Kiska Design to design the bodywork. The aim was to achieve perfect harmony between rider and bike, right down to the smallest detail. The result: new plastics offering perfect ergonomics and contact points for the rider, maximum freedom of movement, a saddle lowered by 10 to 20 mm (at the rear) and improved comfort, particularly at the rear of the saddle.

fuel tank

All SX models feature a new, ultra-light 7-liter polyethylene fuel tank. The internally threaded tank cap ensures easy, reliable closure. Four-stroke models feature an integrated fuel pump system.

graphics

New, modern IML graphics underline the sporty character of the top motocross bikes in the 2016 SX range.

handlebars

The new SX generation models feature a new NEKEN tapered handlebar in high-strength aluminum, mounted on a new clamp equipped with a shock-absorbing gasket and offering two handlebar mounting positions.
All four-stroke models feature a new butterfly assembly with interchangeable cams for different opening characteristics, and new ODI grips with lockable clamp on the left side. A selector allows different configurations to be selected and a start-up control function to be activated.

saddle

Perfectly ergonomic, the new saddle offers superior foam plastic volume, ensuring comfort and durability for the same weight as the previous model.

cooling system

KTM's integrated cooling system routes coolant from the cylinder head through the frame triangle to the new aluminum WP radiators, equipped with a new plug system and made from a stiffer alloy. Thanks to optimized internal circulation and ventilation calculated by CFD simulation, cooling efficiency has been improved by around 10%. Elaborate radiator guards provide effective protection in the event of an accident.

News and media credits: KTM