01. Moteur et silencieux
Weighing in at a lightweight 57.5 lb, this mid-weight powerhouse is the undisputed performance leader in the 250 cc 4-stroke class. Designed and tuned to best suit the performance and handling characteristics of the overall package, the 2023 KTM 250 XC-F sees an increase of power in the mid-range and the top-end. For 2023, the engine is tilted 2° backward with a lower sprocket position, which together with the benefits of mass centralization and reduced weight, makes the anti-squat behavior of the chassis second to none.
The 81 mm bore cylinder houses a forged bridged-box-type piston made by CP. Both, the cylinder and piston are professionally engineered from high-strength aluminum resulting in outstanding performance and reliability. The compression ratio is 14.5:1 which results in notable increases in torque and peak power output.
The fully-redesigned DOHC cylinder head features finger followers with a DLC coating resulting in minimal friction and optimal performance. These actuate large titanium valves - 32.5 mm intake and 27.5 mm exhaust - which at the 14.000-rpm rev-limit open and close multiple times each second for optimum fuel/air mixture. The new 27.5 mm exhaust valve is a result of the redesigned engine to deliver an optimized gas flow.
An important update across the 2023 KTM XC range is an all-new 44 mm throttle body. Taking its learnings from the KTM Factory Racing machines, the injectors are positioned in a double-injector pattern to ensure the most efficient flow into the combustion chamber, while the throttle cable is mounted directly without a throttle linkage providing smoother, uninhibited throttle action. This all adds up to cleaner, smoother fuel ignition, and more power without the fuss.
Designed with weight reduction and performance in mind, the crankshaft in the KTM 250 XC-F engine improves throttle response and contributes to the lightweight feel of the motorcycle. The perfect balance of rotating masses is achieved by balancing the weights of the crankshaft flywheel, the new rotor, and thanks to the innovative counter balancer shaft, engine vibration is kept to an absolute minimum.
The KTM 250 XC-F engine is designed with mass centralization and weight reduction as the main criteria. As a result, the crankcases have been designed to house the internal components of the engine in the perfect position to achieve an ideal center of gravity, while adding the least possible weight. The casings are manufactured using a high-pressure die-cast production process, resulting in thinner but more reliable wall thickness. And just to add a little extra - the KTM brand logo gives the black powder-coated engine cover the ultimate READY TO RACE look.
The KTM XC-F exhaust systems are expertly designed to deliver class-leading performance at the lowest possible weight. Featuring a flow-designed resonance chamber integrated into the 2-piece header pipe, the header pipe remains as compact as possible with the joining position allowing it to be removed without having to take out the rear shock. Further innovation allows for a short, lightweight aluminum silencer without increasing noise levels.
The KTM 250 XC-F features a DS (Diaphragm Steel) clutch, which includes a single-diaphragm steel pressure plate instead of traditional coil springs. The clutch basket is a single-piece CNC-machined steel component, which has been revised to accomodate the new gearbox in 2023, and continues to allow the use of thin steel liners that contribute to the compact design of the engine.