What might be the smallest engine in the KTM 4-stroke range, the 2023
KTM 250 EXC-F packs a surprising punch. With its compact dimensions,
minimal weight, and fantastic handling, the KTM 250 EXC-F has long been a
favorite for motivated amateurs and ambitious pros alike. Thanks to its
advanced fuel injection system, this powerplant also offers
class-leading performance, low-down torque, and confidence-building
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 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 KTM EXC models feature high-tech, lightweight Chromoly steel frames with race-derived geometry, optimal stiffness, and unparalleled feedback for the rider. This translates into a playful handling character, with remarkable stability at speed. The subframe is made of extra-light and ultra-stable aluminum profiles, weighing less than 900 grams providing rear fender stability and durability in the event of a loop out.
The KTM 250 EXC-F features a one-piece aluminum swingarm, which is manufactured using a gravity die-cast production process. This results in exceptional strength at the lowest possible weight and the perfect flex behavior.
KTM uses lightweight, CNC-machined hubs and high-end GIANT rims on all EXC models. These guarantee maximum stability and the bare minimum weight, while aluminum spoke nipples feature an innovative design, which reduces the need to continuously tighten the spokes.
Race-specification, puncture-resistant MAXXIS MaxxEnduro are designed for all-day riding comfort, with extreme grip and performance across any terrain.
Leading the way in enduro-focused suspension, these adjustable 48 mm diameter WP XPLOR upside-down forks provide unmatched performance from both expert and amateur riders alike. Adjustability also comes easily, with compression damping dialed in on the left fork, with rebound on the right.
The race-proven and fully adjustable WP XPLOR shock absorber features conical bushings between the pistons that allow for reduced suspension fade and wear. And, not only this PDS rear suspension design the of choice of champions in the quest for podiums, but it also leads the way when it comes to providing maximum traction for the rear wheel.
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 adjustable, high-strength aluminum tapered handlebars made by NEKEN. These can be mounted in four different positions. Standard with ODI vulcanized grip on the right side and a comfortable ODI lock-on grip on the left, your only worry is hanging on, and letting rip.
Self-cleaning footpegs prevent mud from clogging up the pegs, even when dragging them through deep ruts. This means your boots maintain their grip, and you maintain your focus on the trail.
Go ahead, take a seat. The 2023 KTM 250 EXC-F’s seat is covered in grippy black vinyl, and is perfectly shaped to allow riders complete freedom of movement, but comfortable enough to maintain longer sessions in the saddle.
Drawing inspiration from the RED BULL KTM FACTORY RACING TEAM, the 2023 KTM EXC-F range features an orange-coasted frame and boasts a bold 90s inspired color scheme, using the tried and tested in-mold graphics application for greater friction and fade resistance, meaning your steed will look factory-fresh after even the toughest time spent on the trails.
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.