The smallest model of the KTM 4-stroke range has a surpringly big bite for its size. With its super compact, powerful engine, minimal weight and fantastic handling, its a great choice for motivated amateurs and ambitious pros alike. Thanks to its advanced fuel injection system, this powerplant offers class-leading performance, plenty of torque, great throttle response and controlled power delivery. Additionally, the KTM 250 EXC-F has a lightweight steel trellis frame that contributes to making it even easier to ride, inspiring complete rider confidence and riding progression.
Compact dimensions with class-leading power output, the KTM 250 EXC-F’s fuel-injected DOHC engine is the most powerful and refined 250 cc on the market. Its efficient power delivery is available throughout the entire rev range and with its low weight of only 27.9 kg, this engine is the lightest and most competitive powerplant out there. With Euro IV homologation, it’s not only considerately green, but leaves the competition green with envy too.
The KTM 250 EXC-F engine is fitted with a compact DOHC cylinder head for optimal mass centralization while contributing to even better handling. The head configuration, with double overhead camshafts controlling the gas flow through the ports, promises outstanding, enduro-specific engine characteristics. The DLC coated finger followers, as well as the lightweight titanium valves they actuate (intake 32.5mm, exhaust 26.5mm), allow for higher engine speeds, a crucial factor in the 250’s class-leading performance.
The KTM 250 EXC-F’s crankshaft is located in an ideal position close to the center of gravity, contributing to easier handling. It utilizes a short connecting rod, which makes for an overall compact and lightweight engine with a snappy power delivery. A plain big (bottom) end bearing with two force-fitted bearing shells runs directly on the crank pin. The engine’s pressurized lubrication system provides the necessary oil feed for this bearing. This design has a direct benefit for the crankshaft with extended service intervals, which are lengthened due to the plain bearing. So just pin it, all day long.
CRANKCASES AND ENGINE COVERS
The compact engine cases are manufactured using a high pressure die-cast production process which helps with weight reduction, while retaining strength and durability. The design allows for a very centralized shaft configuration, making the engine very short and compact, while contributing to an efficient centralization of mass. Additionally, the engine covers feature a smart surface structure which reduces wear caused by the rider’s boots, keeping them looking as fresh as the day you bought it.
The KTM 250 EXC-F features a robust 6-speed transmission made by PANKL Racing Systems. The gears are made of a strong, forged raw material, ensuring the highest durability and reliability level. There was no need to change the gear ratios that are perfectly matched to the power characteristics of the engine. All four-stroke engines are fitted with a gear sensor, giving the option of different engine characteristics for each gear.
ENGINE MANAGEMENT SYSTEM
The state-of-the-art Keihin Engine Management System, with electronic fuel injection, features a 42 mm throttle body with separate systems for cold starting and idle adjustment. The throttle cable mount allows for easy access and a smooth routing of the cables. The ECU features selectable engine maps which are optimized to the exhaust, airbox and engine configuration, regulating the unique traction control and are activated by the handlebar map-select switch. It also provides different maps for each gear, according to the information received from the gear sensor, ensuring maximum power as you shift through the gears.
CYLINDER AND PISTON
Inside the short 78 mm bore cylinder, is an extremely lightweight, forged bridged box-type piston made by CP. The piston features a unique crown shape that has been adapted to the combustion chamber. Despite its incredibly low weight, it has an extra rigid structure for enhanced durability. Thanks to its lightweight construction, the oscillating masses are low, giving the engine extremely lively characteristics. The compression ratio of 13.8:1 delivers an exceptional engine performance and reduces the risk of engine knocking.
The multifunctional side-mounted counter balance shaft masterfully balances all the oscillating forces, while also driving the water pump. It effectively keeps engine vibrations to a minimum, resulting in the smoothest ride even at the highest engine speeds.
The KTM 250 EXC-F is fitted with the extremely durable, KTM-developed DS clutch (diaphragm steel), with a wear-free steel basket and heat resistant clutch plates. It uses a diaphragm spring instead of the usual coil springs, which results in considerably easier clutch action. Additionally, the Brembo hydraulic system provides easy and precise clutch modulation throughout the entire operating temperature range.
The standard electric starter on the KTM 250 EXC-F uses a proven starter drive and a strong starter motor made by Mitsuba. As demonstrated time and time again, it provides quick and reliable starting, saving you precious time and energy when you need it most.
Maintaining the optimal engine temperature is crucial to ensuring consistent horsepower throughout the ride. The KTM 250 EXC-F SIX DAYS features radiators which are mounted close to the center of gravity and match the design of the shrouds perfectly, in order to achieve perfect ergonomics. By using CFD technology (Computational Fluid Dynamics) and a smart coolant circuit routing, the innovative system ensures optimum engine temperature for the highest performance, in all conditions. Above all, the delta distributor, integrated into the frame triangle, features a large center tube, making the coolant flow from the cylinder head to the radiators highly efficient. The radiators have special protectors that protect from flying rocks and debris while also acting as a brace to disperse energy around the radiators in the event of an impact.
When it comes to power delivery and performance, the exhaust plays a key role and packs a punch that is hard to beat. All 4-stroke EXC models feature two-piece header pipes which can be disassembled easily and allow easy access to the shock. The aluminum muffler sleeve has a short and compact profile, bringing the weight closer to the center of gravity for better mass centralization.
All EXC models feature high-tech, lightweight chromoly steel frames. This includes hydro-formed elements produced by state-of-the-art robot welding. With its race-proven geometries and optimal stiffness, the frame provides great feedback for the rider, playful handling and remarkable stability. The laterally attached engine head stays (the connection between cylinder, head and frame) are made of aluminum, reducing vibration and further contributing to precise cornering. The bikes also feature lateral frame guards with a structured surface, improving grip, while also serving as a heat protector against the muffler on the right side. The subframe is made of extra-light and stable aluminum profiles, weighing less than 900 gr, providing great rear fender stability.
The KTM 250 EXC-F’s one-piece aluminum swingarm is manufactured using a gravity die-cast production process, offering exceptional strength at the lowest possible weight. The single-component casting process offers low weight, perfect flex behavior and also allows for a large number of geometry solutions.
KTM uses lightweight, CNC-machined hubs and high-end GIANT rims on all Enduro models, guaranteeing maximum stability and minimum weight. The aluminum spoke nipples feature an innovative design, which conveniently reduces the frequency with which the spokes need to be tightened.
All EXC models are fitted with the latest 48 mm diameter WP XPLOR upside-down forks, featuring a split fork design developed by WP and KTM. While each side is fitted with springs, they have separate damping functions. Compression damping is on the left and the rebound on the right. Both can easily be adjusted via the dials on top of both fork tubes with 30 clicks each. Although already distinguished for outstanding response and damping characteristics, the fork features a calibrated mid-valve piston for consistent damping. The settings keep the front end higher in the stroke, providing impressive reserves against bottoming out.
The WP XPLOR shock absorber is the key element on the proven PDS rear suspension design (progressive damping system), where the shock is directly linked to the swingarm without an additional linkage system. This keeps weight lower and reduces the chances of hooking on rocks. Optimal enduro-specific damping progression is achieved by using a second damping piston in combination with a closed cup towards the end of the stroke, and supported by a progressive shock spring. The settings on the XPLOR PDS shock provide impressive damping characteristics and match the frame and front-end set-up perfectly. It is fully adjustable, including high and low-speed compression, so you can set the shock up to suit any track, trail and rider preferences.
These high-tech Brembo babies are combined with lightweight Wave brake discs. You couldn’t brake any harder or with better feel on an offroad motorcycle.
All models in the EXC range are fitted with lightweight polyethylene tanks improving the ergonomics. The ¼-turn bayonet filler cap makes for quick and easy closure. Manufactured using see-through plastic, you will always be able to see how much fuel remains at a glance. It is fitted with an integrated fuel pump system and a fuel level sensor. Additionally, the fuel line features a 90° connector to the tank for better protection against damage.
The airbox on the KTM 250 EXC-F ensures optimal flow dynamics, and together with the intake snorkels, results in optimal power and throttle response. Despite the obvious performance enhancements, the design also offers maximum protection against soiling of the air filter. The large Twin-Air air filter is mounted on a cleverly designed stiff cage that minimizes incorrect installation. As found on previous models, filter maintenance is quick and easy and does not require tools – a standard, original feature from KTM.
All KTM EXC models are equipped with the same high-strength aluminum tapered NEKEN handlebar. The handlebar allows for four different positions. The handlebars come standard with an ODI vulcanized grip on the right side and a comfortable ODI lock-on grip, which does not require any wire or glue, on the left. All models can be fitted with an optional map-select switch on the handlebar for selecting alternative engine maps. The rider also has the option to activate TRACTION CONTROL from this optional switch; a unique feature which guarantees more efficient traction, especially in slippery conditions, and can be activated with the push of a button during riding.
Sophisticated ‘No-Dirt’ footpegs prevent clogging up the pegs, even when digging in deep ruts. The pegs on the Enduro models are 6mm higher than the ones used on SX models, which benefits ground clearance. But you can swap them at will.
Durable in-mold graphics convey the READY TO RACE character of the KTM EXC-F model line.
BATTERY AND WIRING HARNESS
All engines are fitted with the proven electric starter, which is a major benefit for any offroad activity. It is powered by a super lightweight 2 Ah lithium-ion starter battery, which provides safe, reliable starting. A reworked wiring harness and revised packaging has most of the electrical components carefully positioned into a common area below the seat, making them more accessible and reliable.