KTM 250 EXC-F

Fill an agile, state-of-the-art chassis with an engine delivering class-leading power and torque. Then dress it with top class components, ensuring that the new 4-stroke maintains its edge over the competition. The result is a READY TO RACE dual sport suitable for amateur explorers, while still satisfying the pros. Eat that, adversaries.

The main target for the KTM engineers when developing the EXC-F models was a massive weight reduction compared to the previous generation. The result: the current EXC-F’s are the slimmest, lightest bikes in the dual sport segment.

FRAME

The high-tech, lightweight chrome-moly steel frame is engineered for excellent handling, precise cornering and supreme stability. You can also count on high torsional rigidity and low longitudinal stiffness for better absorption of the energy created by the front and rear suspension sucking up jumps and bumps. In short: more comfort and less rider fatigue. Laterally attached, lightweight engine head stays contribute to a reduced vibration level. Two threaded inserts in the lower cradle tubes allow for an optional skid plate. The engineers were able to pull off all that, while making the frame two pounds lighter than that of the lightest competitor on the market. In addition, the frame is easier to maintain, easier to work on and supplies more space for the tank and other components. The bike also features an extra-light aluminum subframe, which weighs in at less than 2 pounds.

FOOTPEGS

Sophisticated “No Dirt” footpegs prevent jamming up of the pegs, even when digging in deep ruts. The pegs on the EXC models are 6mm higher than the ones used on SX models, which benefits ground clearance. But you can swap them at will.

SWINGARM

This updated design allows for an optimized mounting position of the PDS shock, providing more progressive action. Furthermore, the cast aluminum design guarantees lower weight and a perfect flex behavior. The single-component casting process also eliminates any inconsistencies and weak points.

REAR SUSPENSION

The WP XPlor PDS is a newly developed rear shock. The PDS, the KTM proven and successful progressive damping system is kind of a KTM trademark where the shock absorber is directly connected to the upper side of the swingarm. This set-up has now been reworked with the new frame and swingarm architecture in mind. It boasts the best possible mounting geometry, provides even more progressive damping and features an all-new body with a smaller piston and a larger reservoir. The piston diameter was reduced from 50 to 46mm for reduced weight, the total length is reduced by 2.5mm and the shock stroke has been reduced by 4mm. In addition, it is now mounted 5mm closer to the centerline, which means nearly symmetrical loads for the swingarm and frame and more space for the exhaust. A second piston works together with a closed cup (instead of a needle) towards the end of the stroke and is supported by a progressive shock spring for exceptional bottoming resistance. With this new design comes a weight savings of 1.4 pounds. Various machined and anodized components and a distinctive WP color trim make this a valuable, high-end product compared to the less refined shocks of the competition.

FRONT SUSPENSION

The all-new WP XPlor 48 upside-down fork is a split fork developed by WP in close collaboration with KTM. It is fitted with a spring on both sides but features separated functions for each fork leg: compression damping is fitted on the left side, while rebound is on the right. So the forks can easily be adjusted for compression and rebound with the twist of a dial on the top of the forks. In addition, a longer and sealed hydro-stop guarantees better resistance to bottoming-out. Due to high-quality materials and a state-of-the-art production process, the new XPlor 48 fork – with approx. 300mm of travel – has outstanding response and damping characteristics and is about a half of a pound lighter than its predecessor.

BRAKES

You can’t brake any harder, better, faster or stronger. High-tech Brembo calipers are combined with lightweight wave discs and feature a reduced piston diameter for better modulation. The rear brake now features a 10mm longer brake pedal, and less aggressive brake pads are fitted front and rear. The steel-flex front brake hose gets more efficient protection and there’s an integrated channel for the speedo cable. First you outrun them, then you outbrake them.

HANDLEBARS

KTM engineers know how to handle handlebars. This tapered unit, made of high-strength aluminum by NEKEN, features a newly developed throttle assembly with a robust aluminum body and easy free-play adjustment. An ODI volcanized grip sits on the right, while on the left side of the bar a comfortable ODI lock-on grip requires no glue or wire to secure it.You can now retrofit two interchangeable throttle cams, for different response characteristics to suit your specific needs.

TRIPLE CLAMPS

The new generation is fitted with forged triple clamps with an offset of 22mm, ensuring a solid grip of the fork and precise handling. The handlebar is adjustable forwards and backwards over 4 positions, so the EXC-F will fit you like your favorite gloves.

ENGINE

The new 250 EXC-F engine has been redesigned in order to make the new powerplant more compact and lighter, while delivering class-leading torque and power figures over the entire rev range. A new architecture with an optimized shaft configuration makes the engine 20mm shorter, contributing to the bike’s mass centralization and effortless rideability. Another major benefit of the new design is the weight reduction of 3.3 pounds; that’s including the comfort of the electric starter. The power curve has increased over the entire length of the 12,800 rpm rev range. This makes the new 250 EXC-F brilliantly suited to both amateur riders as to pros at the peak of their ability.

CYLINDER HEAD

The centerpiece of the compact DOHC engine is this cutting-edge cylinder head. It features lightened dual overhead camshafts with friction-optimized finger followers boasting a 30% harder DLC coating and a reworked timing drive. Four lightweight titanium valves and high-flow ports maximize the flow rate for an optimal power band and outstanding performance across the seemingly endless rev range of 12,800 rpm. Two new lateral stays allow an efficient fixation of the engine to the frame and reduce vibration.

CRANKSHAFT

The 250 EXC-F’s crankshaft utilizes a 6mm shorter connecting rod, making for an overall compact and lightweight engine with a snappy power delivery. A plain big-end bearing with two force-fitted bearing shells runs directly on the crank pin. This design is a must for the extremely high engine speeds and the unrivaled power of this 250 cc engine while also enhancing the engine’s durability for long crankshaft service intervals.

ELECTRIC STARTER

The 250 EXC-F is fitted with an electric starter as standard, which is a clear advantage when things get gnarly. A strong starter motor made by Mitsuba powered by a reliable lithium ion battery and KTM’s proven starter drive will fire up time again at the push of a button.

ENGINE CASES AND COVERS

The completely new design of the die-cast engine cases allowed for a much more centralized shaft configuration, moving the crankshaft closer to the bike’s center of gravity. The clutch shaft position has also been moved 11.1mm back and 26.9mm up, shortening the engine by another 2cm. All hail mass-centralization! Newly designed engine covers feature an advanced surface structure in order to reduce the wear caused by the rider’s boots.

TRANSMISSION

The new engine is fitted with a precise six-speed Enduro gearbox, with solid shift engagement thanks to a special low-friction coating on the shift forks. An advanced ´No Dirt´ gear lever design prevents mud or dirt build-up in the joint for trouble-free rides. All KTM 4-stroke engines are fitted with a gear sensor that syncs the power curve to the gear selection.

ENGINE MANAGEMENT SYSTEM

The state-of-the-art Keihin Engine Management System with electronic fuel injection features an all-new 42mm throttle body. Thanks to its unique injector position, the engine’s response gives a whole new meaning to the word ‘instantaneous’. Separate circuits for cold-starting and idle make on-site adjustments easy. Push the throttle back when the engine is warmed up and the cold start mode disengages.

CLUTCH

The 250 EXC-F employs the KTM-developed DDS clutch (damped diaphragm steel) with a wear-free steel basket and extremely heat resistant clutch plates. This clever design employs a diaphragm spring instead of the usual coil springs, making for considerably easier clutch action. A diaphragm spring also leaves sufficient space for a damping system to be integrated into the clutch hub. The goal is traction, but durability is as well. A lighter basket, a reworked inner hub and a pressure plate providing better oil supply and unsurpassed cooling up the longevity of the DDS clutch. Light operation and telepathic amounts of control are standard with this hydraulic Brembo actuated clutch.

COUNTER BALANCE SHAFT

In order to balance the mass forces, the engine uses a multifunctional counterbalancer shaft that also drives the water pump and reworked timing chain.

CYLINDER AND PISTON

Inside the shortened cylinder, with a bore of 78mm, thumps a reliable box-type piston made by CP. Its crown geometry is adapted perfectly to the high-compression combustion chamber (12.8:1), where its rigid structure and low weight maximize performance. Thanks to low oscillating masses, the engine revs freely with plenty of power.

BODYWORK

KTM R&D, Kiska Design and the factory racers had their say in shaping the plastics with one goal: complete harmony between rider and bike. Perfect ergonomics and contact points provide maximum comfort in movement on the EXC-F. The I-beam structures of the front and rear fenders guarantee maximum stability and a low weight thanks to well thought-out construction and mounting. They also stay cleaner for longer. Cleaver brake hose routing on the front number plate prevents wear and tear.

GRAPHICS

New graphics convey the READY TO RACE character of the 2017 EXC-F model line.

AIRBOX

The airbox design, featuring new snorkels, offers maximum protection of the air filter against soiling, while ensuring maximum airflow in a quiet way. The new, large Twin Air filter is mounted in a stiff cage, which at the same time holds the system in place. This design is so simple, you can pop a fresh one in with a face full of mud – without tools and in seconds.

FUEL TANK

The lightweight polyethylene tank has a capacity of 2.5 gallons. You will always be able to see how much fuel remains at a glance, thanks to the see-through plastic. By pushing the orange release button in the center of the filler cap, the bayonet mechanism makes refueling quick and easy. The 4-stroke models are fitted with an integrated fuel pump system and an additional fuel level sensor. Additionally, the fuel line features a 90° connector to the tank for better protection against damage.

EXHAUST

Noise limits are a real challenge for every manufacturer. Therefore, KTM has put a lot of effort into the development of its exhaust systems. All 4-strokes are fitted with new header pipes and a shorter silencer, mounted as close to the engine as possible. This means more power, extra mass centralization and better rideability. An advanced internal design reduces the noise sufficiently in order to sit safely below the noise limit, while still providing the engine response and performance that is expected from a KTM.

WHEELS

The EXC-F’s wheels feature lightweight, CNC machined hubs and high-end Giant rims guaranteeing maximum stability at minimum weight. The wheels are fitted with the Continental TKC 80 tires – perfect for surefooted performance off-road and stability on-road

COOLING SYSTEM

KTM’s proven cooling system routes the coolant from the cylinder head through the frame triangle, directly to aluminum radiators made by WP. A new filler cap system and are stiffer alloy construction increase the durability and reliability of the cooling system. Due to flow optimized internal circulation and CFD-calculated air ventilation, the system is superbly efficient. In addition, well thought-out radiator guards integrated in the front part of the shrouds provide protection in a crash.

SEAT

Tailored to meet the needs of the best off-road racers, this durable seat offers great comfort, while being 10mm lower to help you master the most challenging terrain.

BATTERY & WIRING HARNESS

This new engines is fitted with KTM’s proven electric starter – a unique KTM feature and a major benefit at all levels of racing. A super compact 495g lithium ion starter battery breathes life into the engine, shaving off two pounds of excess weight while offering three times the starting energy of a conventional battery. Because of its reliability, we decided to eliminate the kick-starter entirely. The battery and wiring harness are centralized in a compartment above the airbox, allowing the mechanic to remove the subframe without having to remove the electronics.