KTM 250 SX‑F 2015: THE ULTIMATE WINNING BIKE
SUPERIOR CHASSIS
FRAME
The modern frame design of the SX models, comprising lightweight, high strength, chrome-molybdenum steel section tubes, combines maximum longitudinal stiffness with optimum torsional stiffness. A forged and milled cross-tube connects the two frame halves with the connecting rod of the linkage on the new SX frame for 2015. Omission of the weld seams leads to very precise manufacturing tolerances and greater safety - moreover, it saves another 60 grams of weight.
LINKAGE / SHOCK ABSORBER
The revamped damping system for MY 2015 features a new linkage with optimised geometry. The flatter progression with a higher initial rate ensures greater stability and lowers the rear end. In addition, the new design saves another 40 grams of weight. The fully adjustable WP 5018 shock absorber has been completely retuned to suit the new linkage.
TRIPLE CLAMPS
High quality, CNC-machined triple clamps have long since been standard equipment at KTM. They ensure precise handling and provide a perceptible boost to the flexing characteristics and hence the responsiveness of the telescopic fork. The new O-ring carrier for the lower steering head bearing, a revised shaft tube and the new steering head bolt save another 40 grams.
FORK
The fully adjustable upside-down fork from WP Suspension has been perfectly tuned to the new rear wheel damping system and the new 22 mm front axle (formerly 26 mm) for MY 2015. The new axle provides a better feel for the front wheel and also saves a further 40 grams. The new fork stubs now feature an offset of 33 mm instead of 35 mm, which together with increased trail deliver greater ride stability. Furthermore, they accommodate newly developed, 50 gram lighter fork protectors.
TOP ERGONOMICS
BODYWORK
KTM engineers have focussed on designing the bodywork ergonomically and functionally in such a way that the whole motorcycle is in perfect harmony with the rider down to the very last detail. The front fender is a perfect example of how moulded plastic components can gain maximum stability with a well thought out structure and well-conceived attachment.
GRAPHICS
A new, refined graphic design with clear lines underlines the high demands made of a modern, state-of-the-art offroad motorcycle.
SEAT
The ergonomically perfectly designed seat is equipped with a durable foam core, ensuring both adequate comfort and high stability.
AIRBOX
At the same time, the design of the airbox guarantees optimum protection of the air filter from dirt plus maximum air throughput for the highest performance. Quick replacement of the twin-air filter - without tools and in a matter of seconds - has long since been an unrivalled KTM standard.
FUEL TANK
All models in the SX range are equipped with a 7.5 litre, lightweight polyethylene fuel tank. The fuel pump system used on the 4-stroke motocross models is the same as that used on the 4-stroke enduro models, thereby allowing optional fitting of larger tanks from the PowerParts range or from the enduro models.
HANDLEBAR
All SX models are equipped with the extremely sturdy, tapered Renthal Fatbar 827 handlebar that features an offset specially designed to meet the demands of motocross. In accordance with the proven KTM standard, the handlebar can be fixed in a choice of four positions. For MY 2015, it is equipped with softer two-component grips to spare the rider's hands.
UNRIVALLED HANDLING
WHEELS
The wheels fitted for MY 2015 feature black coated, high-end Excel rims with lightweight, CNC-machined hubs and spokes with lightweight aluminium nipples, allowing highest levels of stability to be achieved, while keeping weight to a minimum. New Dunlop Geomax MX 52 tyres were developed in collaboration with the KTM USA factory team and offer perfect traction with top performance. The new rear sprockets save 50 grams in unsprung mass.
BRAKES
High-tech brakes from Brembo have always been standard equipment on KTM offroad bikes and, together with the lightweight wave brake discs, they are the measure of all things in terms of brake technology. As the best brakes in the motocross class, they remain unchanged for MY 2015.
BETTER PERFORMANCE
ENGINE
The 250 SX‑F is virtually a guarantor for top places in hard-fought motocross battles – this is substantiated not only by the numerous world titles. Newly developed oil strainer sealing rings are used for MY 2015 to provide better durability in the most extreme conditions and a longer service life. The combination of compact engine design and unrivalled performance make the 250 SX‑F an undisputed contender in the next model year as well.
COOLING SYSTEM
The tried and tested, integrated cooling system transports the coolant from the cylinder head through the frame triangle directly to the aluminium radiators made by WP. The consequent lack of piping simplifies radiator installation and improves air flow beneath the fuel tank.
ENGINE MANAGEMENT SYSTEM (EMS)
In conjunction with the revolutionary injector position developed by KTM, the Keihin engine management system (EMS), with electronic fuel injection and 44 mm throttle body, ensures spontaneous responsiveness and maximum engine performance. Various engine characteristics can also still be selected via the EMS, with a map-select switch available as a PowerPart. Furthermore, a user-setting tool (also available as an option) allows data to be read from the bike by laptop and the mapping, ignition and fuel injection to be modified in a matter of a few mouse clicks.
CYLINDER HEAD
The heart of the compact DOHC engine is the state-of-the-art cylinder head with twin overhead camshafts and DLC-coated cam followers – a design allowing the rev "sound barrier" of 14,000 rpm to be achieved. Ducts designed for optimum flow combined with ultra-light titanium valves (intake 32.5 mm, exhaust 26.5 mm) guarantee maximum gas throughput and therefore the highest performance.
PISTON
The forged piston with a box-in-box design excels with its extra-stiff structure, while keeping weight to a minimum. Thanks to its reduced reciprocating weight, the engine exhibits extremely dynamic characteristics.
CRANKSHAFT
The crankshaft on the 250 SX-F is equipped with a plain bearing in the lower conrod eye. Two press-fit bearing shells run directly on the crankshaft's crank pin. This design is a key factor behind the extremely high engine speed and unrivalled peak power of the 250cc engine. It also enhances the durability of the engine, thereby enabling an extension to the service intervals for the crankshaft – a benefit for the customer in terms of time and costs.
BALANCER SHAFT
To counterbalance the inertia forces, the 250 SX-F engine is equipped with a balancer shaft that acts as a multi-function shaft, driving timing chain and water pump simultaneously.
STARTER
The 250 SX-F engine is equipped as standard with an electric starter – an undisputed benefit when the going gets really tough in the heat of battle, even when a slight weight disadvantage has to be accepted as a consequence.
CLUTCH
The very compact CCS (Coil Spring Steel) clutch is equipped with a wear-free steel cage and eight lining discs that are extremely heat-resistant due to the steel base material. The clutch basket has been reworked to make it lighter for MY 2015. The clutch springs are made from a new material that provides more consistent behaviour both in tough conditions and for a longer time. The hydraulic clutch actuation system from Brembo guarantees smooth and very precise clutch control.
TRANSMISSION
The lightweight 5-speed transmission excels with extremely precise and simple shifting, so precisely the right gear ratio can be selected effortlessly in every situation.
The 250 SX-F has been an established force in the MX2 World Championship for years now. In addition to the world title, it also won the prestigious AMA Supercoss Lite Championship in 2013. All over the world, in both professional and amateur classes, the 2013 motorsport season was very successful for the 250 SX-F - and the 2014 season promises to be no different. In MY 2015, the feisty 4-stroke hits the scene with further improvements to engine and chassis – a performance package that will continue to dominate the MX2 class.
TECHNICAL DETAILS
ENGINE
| Design | Single-cylinder, 4-stroke, spark-ignition engine, liquid-cooled |
|---|---|
| Displacement | 249.91 cm³ |
| Bore | 78 mm |
| Stroke | 52.3 mm |
| Starting aid | Electric starter |
| Transmission | 6-speed, claw shifted |
| Engine lubrication | Forced oil lubrication with 2 Eaton pumps |
| Primary ratio | 24:73 |
| Final drive | 13:50 |
| Cooling system | Liquid cooling system, continuous circulation of cooling liquid with water pump |
| Clutch | Wet multi-disc clutch / Brembo hydraulics |
| Ignition system | Contactless, controlled, fully electronic ignition system with digital ignition timing adjustment |
CHASSIS
| Frame | Central tube frame made of chrome molybdenum steel tubing |
|---|---|
| Fork | WP Suspension Up Side Down 4860 MXMA 4CS |
| Shock absorber | WP Suspension 5018 BAVP DCC |
| Suspension travel Front | 300 mm |
| Suspension travel Rear | 317 mm |
| Brake system | Disc brakes, brake calipers on floating bearings |
| Brake discs - diameter Front | 260 mm |
| Brake discs - diameter Rear | 220 mm |
| Chain | 520 X-ring |
| Steering head angle | 63.5° |
| Wheel base | 1,495±10 mm |
| Ground clearance (unloaded) | 375 mm |
| Seat height (unloaded) | 992 mm |
| Total fuel tank capacity approx. |
7.5 l Unleaded premium fuel (95 RON) |
| Weight without fuel approx. | 102.2 kg |
