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. For the 2014 model year, KTM engineers have equipped the engine with, among other things, a lighter transmission featuring five instead of six gears. The combination of compact engine design and unrivalled performance make the 250 SX‑F an undisputed contender in the next model year as well.

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. A redesigned starter freewheel is employed in MY 2014 for the benefit of greater durability.

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.

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.

PISTONS

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 new 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. For the 2014 model year, the engine is provided with a new water-pump cover complete with new gasket for optimising sealing.

TRANSMISSION

The 250 SX‑F engine excels in MY 2014 with a new transmission characterised by extremely precise and simple shifting. With the number of gears reduced from six to five, the new transmission is 250 g lighter than its predecessor.

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 hydraulic clutch actuation system from Brembo®, with new clutch armature, guarantees smooth and very precise clutch control.

ENGINE MANAGEMENT SYSTEM (EMS)

In conjunction with the revolutionary injector position developed by KTM, the Keihin engine management system, with electronic fuel injection and 44 mm throttle body, ensures spontaneous responsiveness and maximum engine performance. The wiring harness on the 250 SX‑F has been further simplified for the 2014 model year and the quality of cables and plugs improved. Many connectors are now enclosed in new rubber grommets to protect them from steam-jet pressure. 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.