250 SX-F 2013 - OVERVIEW
The KTM 250 SX‑F has been an established force in the MX2 World Championship for 8 years now. And the new generation appears with a completely new, even lighter engine and an updated injection system. In other words: a performance package that will redefine the MX2 class. Together with a new frame and new bodywork, the new KTM 250 SX‑F 2013 is a winning bike that dominates the MX2 class.
REAR SUSPENSION »
The linkage rear suspension with WP shock absorber was reworked for MY2013 for all models. Beside some weight reductions of bolts, bearing cups and washers of the linkage system the settings of the shocks have been completely updated. In addition the 350 SX-F is fitted with a harder spring. Of course it is KTM standard to a low individual clicker adjustment (rebound and high/low speed compression damping) for any kind of rider and race track.
SWING ARM »
Aluminium cast swing arm provides perfect stability at minimum weight. For MY2013 the swing arm is reinforced and now allows the mounting of a larger rear axle to work together with the new frame concept for improved riding stability.
Modern and lightweight frame design made of chromoly steel provides optimal mix of stiff-ness and flexibility for maximum track stability, easy handling and precise cornering.
After just two years the bodywork is completely reworked to further improve the bike ergonomics and indicate clearly, that model year 2013 means a new generation for KTM SX.
FRONT SUSPENSION »
The further improved 48 mm WP closed cartridge Upside-Down fork shines with completely reworked settings for all models and harder springs for 250 and 450 SX-F. A newly developed fork oil provides reduced friction and improved durability for more constant damping characteristics during its entire life cycle.
FUEL TANKS »
The 7.5 litre fuel tanks have been reworked for 2013 to match the shape of the new spoilers for improved ergonomics. In addition they feature a new inner screw-type fuel cap.
TRIPLE CLAMPS »
Further developed CNC machined triple clamps improve the bike´s stability and provide improved fork clamping, supporting the fork action due to reduced friction and better bending characteristics. In addition the lower clamp features a weight reduction of 80g due to the reworked design. The front fender is attached by two screws on the bottom and two in the front.
Newly designed airbox and cover provides more space for the TWIN AIR filter. New intake snorkels for all 4-stroke models allow for better airflow and higher performance. The exchange of the airfilter is possible without any tools in just a few seconds. The airbox cover features standard clips to be fixed, optionally it can be secured by an additional screw.
High strength EXCEL rims, CNC machined hubs and new spokes coated in black guarantee maximum stability. The Pirelli Mid Soft 32 tires stand for outstanding traction. A stronger rear axle (20 >25 mm) improves the stability of the bike.
All models are fitted with new 827 Renthal Fatbar handlebars featuring the equivalent bend of the 996 Twin-wall. New 2-compound grips with KTM logo provide excellent contact to the bike.
EXHAUST SYSTEM »
Future noise limits will be a real challenge for every manufacturer, therefore KTM put a lot of effort into developing new exhaust systems for all 4-stroke models, which meet the tough limits of the 2013 season and even improve the bikes performance.
COOLING SYSTEM »
The proven cooling system is transferring the cooling liquid from the cylinder through the frame triangle to the new WP radiators.
The proven Brembo brakes in combination with the WAVE discs and stainless steel brake lines provide the best brake performance. The rear caliper carrier is adapted to the larger rear axle.
A completely new graphic design in conjunction with the new bodywork is a clear statement to underline the performance of the new SX generation.
The completely new engine of the 250 SX-F incorporates the latest engine technology and shines with an extremely lightweight and compact design and outstanding power output. The performance of the new 250 SX-F generation is the clear benchmark for the MX2 class due to a shorter stroke and larger bore, a new cylinder head layout and a higher rpm range.
CYLINDER HEAD »
The basic design of the new DOHC cylinder head with four titanium valves, two cam-shafts and finger followers follows the same design philosophy as the successful 350 SX-F but internally it is designed for the 250 engine without any compromise. Compared to the predecessor the new 250 SX-F has larger ports, an optimised combustion chamber, larger intake valves and new camshafts guaranteeing a significant power increase of + 5 hp.
ENGINE CASES »
The new 250 SX-F is now fitted with completely new engine cases produced in high pressure die cast instead of sand cast. This is a precise casting method for thinner wall thickness. This means a massive weight reduction together with the elimination of the kickstart casting.
CYLINDER & PISTON »
The newly designed cylinder carries a extremely lightweight box-in-box piston with a 2 mm larger diameter compared to My 2012 (76 > 78 mm), which allows higher rpm and gives space for larger valves due to the larger bore.
COUNTER BALANCE SHAFT »
The new 250cc engine is now fitted with a laterally mounted counter balance shaft, which at the same time drives the water pump and timing chain. This solution allows a very compact and lightweight engine design.
CRANK SHAFT »
The completely new crank shaft has a 2.5 mm shorter stroke and carries less inertia for more spontaneous power delivery. Like all the KTM factory bikes the crank shaft is fitted with a Pankl connecting rod featuring a plain bearing (no more needle bearing), which allows higher rpm and less maintenance.
Like all factory bikes the 250 SX-F is fitted with a reliable and lightweight electric starter. This is an outstanding feature and means a major advantage especially when restarting after a crash, even though this solution means higher weight compared to a pure kickstart engine. For maximal weight reduction the new engine no longer gives the option of mounting a kickstarter. As proven by the KTM factory riders the advantage of the electric start is much more important than the weight penalty.
The new 250cc engine is fitted with the same clutch as the 350 SX-F featuring a lightweight, one-piece CNC machined basket made of steel, which allows the use of thin steel linings for maximum compactness. The Brembo hydraulic system provides easy and precise modulation.
The new 6-speed gear box is adapted to the new engine design and provides the same final gear ratios as the predecessor.
ENGINE MANAGEMENT SYSTEM »
For MY2013 the Keihin EMS was radically reworked. A new throttle body features a bore of 44 instead of 42mm for higher airflow. Together with an improved injector and a new injector position (spraying upwards) the new EMS contributes a lot to the massive power increase. A new throttle position sensor (TPS) is more resistant against water and is protected by a plastic guard. The wiring harness is further improved with longer lead wire and critical connectors are now protected via rubber caps. The small in-line screen is now positioned in the quick-change fuel line connector for easier access. The idle adjuster is now isolated from the cold start button and located in the back of the throttle body.