Even though KTM only introduced a brand new EXC generation in 2017, the challenges never stop.

This means research and development also never cease at the Austrian headquarters, and so in 2018, KTM is once again set to deliver the next revolutionary game-changer in competition off-road sports: the world’s first two-stroke, off-road competition bikes with serial, electronic fuel injection.

Combining top performance and outstanding rideability, the KTM EXC TPI models with 250 and 300 cc of displacement will be distinguished by the lowest weight in their class, intuitive handling and a unique style, along with the awesome READY TO RACE performance expected of any genuine KTM race bike.


“TPI” stands for “transfer port injection”, and the groundbreaking new two-stroke represents another major step forward on a global scale, once again demonstrating KTM’s unrelenting and continuous commitment to two-stroke technology as such. The benefits to owners are clear: besides huge improvements in fuel efficiency and clean exhaust emissions, the electronics do away with the need for re- jetting, no matter the elevation of the race venue, prevailing weather conditions and the like.

Don’t Miss: Browse to the bottom to see the huge TPI gallery

Also, engine lubrication on the TPI models is automatic from a separate oil tank and electronically controlled oil pump, obviating the use of pre-mixed fuel-oil mixture.

In short: TPI means a new dimension of READY TO RACE DNA in every detail. And more than that: TPI is the living proof that KTM’s ongoing commitment to off-road racing in general will never stop, and its dedication to two-stroke technology in particular is alive and well. In fact, the state of the art R&D department in Mattighofen is expanding, while the new motorsport division demonstrates KTM’s growth and continuing investment.

Because off-road racing is nothing less than the very foundation of the company.

Once again a highly exciting racing season lies behind us. For the KTM Enduro Factory Racing riders it was a season of success for some, while overcoming the biggest challenges for others. It’s fair to say that KTM continues to be a mainstay in the battle for supremacy across all disciplines.

KTM two-stroke racers especially made headlines in 2016 with Jonny Walker attacking the toughest, most difficult terrain, like at Red Bull 111 Megawatt where the British-ace managed to come back from a leg injury earlier in the year to win the event in spectacular fashion. True grit and a true lover of the two-stroke machines, Jonny cannot wait to switch to the new, fuel-injected two-stroke EXC TPI machine full time.

Jonny’s teammate, Alfredo Gómez from Cercedilla in Spain, joined the KTM Factory Racing team in 2016. Soon after, the Spanish-ace delivered wins at Red Bull Minas Riders and The Wall Extreme Enduro, plus multiple podiums aboard his EXC racing machine throughout the season. A feat he looks to build upon this year.

Another clear sign of the global trend back towards the two-stroke racing categories is three-time world champion Christophe Nambotin switching back to two-stroke for the 2017 season. The future looks strong with the new KTM EXC TPI engines and investment in this area – the factory team is highly excited to race the new TPI machines as soon as possible after their launch. Besides the performance boost, their increased fuel economy and much less complex setup are bound to translate into huge benefits for riders and mechanics alike, for both classic and Extreme Enduro events.

Of course, the 4-stroke faction has been anything but idle, as witnessed by another incredible achievement, with Laia Sanz winning the Women’s Enduro World Championship for the fifth time in a row on her KTM 350 EXC-F in 2016! And switching over from Motocross, Nathan Watson from Nottingham, UK rode to second place in the 2016 E1 category in his first year in the Enduro World Championship. A highly impressive result with his KTM 250 EXC-F, which propelled the youngster to race the higher capacity machine in 2017.

Lastly, not to forget the globally important International Six Days Enduro where USA’s Taylor Robert topped the E2 category standings and took the overall win at the event, while Australian rider Daniel Sanders, who joins the KTM Factory Racing team this year, finished as the E3 class winner and runner-up overall. The top two women Maria Franke and Laia Sanz were also aboard KTM machinery, highlighting KTM’s international dominance in Enduro once again.

The new KTM 250 and 300 cc Enduro models fitted with the revolutionary TPI serial fuel injection are high-end, READY TO RACE products, which set new standards in the two-stroke segment. TPI stands for „transfer port injection”; a global-first, groundbreaking technology for two-stroke racing engines that de- livers a previously unattainable combination of top performance and outstanding rideability. Lubrication is taken care of by an automatic system with a separate oil tank and electronically controlled oil pump instead of using premix.

In addition, the TPI bikes benefit from the complete set of KTM Enduro racing features such as an E-starter powered by super-lightweight lithium ion batteries, sublime Brembo brakes, self-adjusting hydraulic clutches, KTM ‘No Dirt’ footpegs and gear shift levers, KTM toolless air filter boxes, quick- release fuel lines, polished hubs, WP Xplor 48 split forks, WP Xplor PDS shock absorbers and of course typical KTM precision-welded chromoly frames. This means they are not only among the lightest bikes in their respective classes, but they also deliver intuitive handling, while the exclusive bodywork sets them apart with a unique style.


The TPI engines are fitted with a newly developed 39 mm throttle body made by Dell’Orto. Power is controlled by a throttle valve and two throttle cables via a newly developed handlebar throttle assembly group. Intake air data is provided to the engine management system by a throttle position sensor, while an adjusting screw allows the idle speed to be set. A cold start device is also provided, opening a bypass to supply extra air. Oil supplied by the automatic oil pump via an oil suction pipe is mixed with the incoming air to lubricate the moving engine parts.


The European stage 4 emission standards for motorcycles have been in effect since January 1, 2016, using the World Motorcycle Test Cycle (WMTC) and once again establishing stricter limits for motorcycle exhaust emissions. Thanks to the highly efficient combustion control of the TPI system and precise automatic engine lubrication, the new KTM EXC models will be Euro-4-compliant, not the least due to their significant reduction of hydrocarbon emissions.


An oil pump mounted underneath the oil tank delivers the lubricant to the throttle body, where minute quantities are mixed with the incoming air in order to lubricate the moving engine parts. Using engine speed and throttle position sensor data, the engine management system’s precise electronic control of the oil pump ensures the perfect amount of oil for any given conditions, loads and engine speeds is added.

The filler cap assembly for the oil tank is located between the fuel tank and steering head, utilising a hose in the upper frame tube to conduct the oil to the storage container. Automatic, electronically controlled oil injection reduces exhaust smoke by up to 50% over conventional pre-mix lubrication, with an average fuel-to-oil ratio of 1:80. This means the oil capacity of about 0.7 litres is sufficient for at least five tanks of fuel.


While the core dimensions and layout of the TPI cylinders are carried over from the carburettor model with bore diameters of 66.4 and 72.0mm, respectively, the new cylinders feature two lateral domes holding the fuel injectors that inject fuel into the rear transfer ports. This downstream injection guarantees excellent atomisation of the fuel with the upstreaming air for a highly efficient combustion and significantly reduced losses of unburned fuel. The engine management system’s intake pressure sensor is connected via a small-diameter tube in the back of the cylinder. For a smooth and well-con- trolled power delivery, the sophisticated exhaust control of the carbureted EXC models is also retained.


For optimal mass centralisation, the lightweight, die- cast crankcases hold the clutch shaft and the crank- shaft in a high position close to the centre of gravity supporting the handling of the bike. In addition, this design allows the implementation of a lateral balancer shaft to minimise vibrations, enhancing comfort and reducing rider fatigue during long and demanding Enduro events and rallies.


The KTM EXC TPI models employ the KTM-developed DDS clutch (damped diaphragm steel) with a highly resilient steel basket and extremely heat resistant clutch plates, a design distinguished by a considerably easier clutch operation than with conventional coil springs. The diaphragm spring also leaves sufficient space for a damping system integrated into the clutch hub, which benefits both traction and durability.

The hydraulic Brembo clutch mechanism is synonymous with a light action and highly controlled clutch modulation.


A newly developed control unit and a new wiring harness with five sensors.

Based on a newly developed electronic control unit located below the seat, the new KTM EXC TPI models feature the most modern engine management system (EMS) of any 2-stroke off-road motorcycle. Utilising various sensor data such as intake and ambient air pressure, throttle valve position and water temperature, the control unit optimises ignition timing and the amount of fuel to inject. Thanks to its automatic altitude and temperature compensation, there is no need for the rider or mechanic to set up the bike for the prevailing environmental conditions. Should the rider decide to mount an accessory radiator fan from the KTM PowerParts program, it will also be controlled directly by the EMS without adding a temperature switch. An optional map select switch (standard on the SIX DAYS models) allows the rider to select an alternate map, providing a smoother power delivery.


In order to accommodate the power requirements of the upgraded engine management system, the TPI models are fitted with a more powerful generator, rated at 196 W, just like on the EXC-F 4-stroke models, as well as the EXC-F voltage regulator.


The rugged 6-speed transmission features widely spaced gear ratios optimised for Enduro duty. It provides precise and easy shifting. The KTM ‘No Dirt’ gear shift lever design prevents residue from blocking the joint of the gear shift lever for safe and reliable shifting in any conditions.


The EXC TPI models are equipped with E-starters located in a well-protected position on the undersides of the engines. A powerful but lightweight lithium ion battery provides convenient and reliable starting.


The rear subframe made of lightweight aluminium sections is connected to the frame with four bolts and weighs a mere 900g.


The frames of all KTM off-road models are manufactured from lightweight sections of top-quality chrome-molybdenum steel tubing of various cross sections. This type of frame design provides high torsional rigidity for best handling and rideability, while a certain longitudinal flexibility can absorb the wheel impact energy, supporting the suspension for reduced rider fatigue. At the same time, the frame triangle serves to deliver the coolant from the cylinder head directly to the radiators.

In the TPI models, the modi ed frame design also serves to route engine oil from an added filler cap assembly, located between the fuel tank and the steering head, via a hose inside the upper frame tube to the oil tank.


The air filter box design offers maximum protection of the air filter against soiling while ensuring maximum air flow. It uses a large Twin Air filter element mounted on a rigid cage which at the same time forms the air filter box bracket. The straightforward design also minimises the risk of installing the air filter or cage incorrectly.

An original staple of practical KTM design, the filter is quickly and easily changed without tools in seconds. In addition, the new TPI 2-stroke models are fitted with a new velocity stack to match the throttle body while at the same time accommodating an intake air temperature sensor.


All KTM EXC models feature lightweight, translucent polyethylene fuel tanks that make it easy to gauge the fuel level from the outside. Along with the new injection system, the TPI models receive a new, 9L tank with an integrated fuel pump system like the 4-stroke bikes and an additional fuel level sensor.


The time has come to give a new shockwave to the 2-stroke segment and send the clear message that the future of the technology is bright, as it has now become possible to combine its outstanding power-to-weight ratio, low cost and simplicity with clean exhaust emissions and a low fuel consumption. For model year 2018, the cutting-edge and lightweight 250cc 2-stroke features an all new engine management system with the revolutionary TPI fuel injection – the world’s rst serial electronic fuel injection system for 2-stroke off-road racers. The TPI technology (transfer port injection) has been developed by KTM in close co-operation with EFI specialist Synerject. Turning the 2-stroke world upside down, it makes engine operation not only remarkably cleaner, but also provides a more consistent performance. While engine power remains at the same level, the power delivery is much more homogeneous.

Compensating automatically for air pressure and temperature, there is no need to set the TPI bike up for the elevation and weather of the race location. Premix fuel with 2-stroke oil is also a thing of the past, and the fuel efficiency increases dramatically.

With this state-of-the-art powerhouse fitted in an extremely lightweight chassis, the upcoming KTM 250 EXC TPI excels on all sorts of tracks and terrains. Combining the handling benefits of its low weight with the advantages of the TPI engine results in an outstanding performance to make it a formidable contender against the more complex 4-strokes. At the same time, the new bike remains a great choice for all riders who just love the low purchasing and maintenance costs and the typical 2-stroke sound.


  • Reduced fuel consumption
  • Automatic elevation compensation, no re-jetting required
  • Enhanced rideability and performance
  • Reduced emissions
  • Smooth engine behaviour
  • Reduced fuel evaporation, which also means less fuel smell in transport vehicles
  • Enhanced comfort and convenience: easy starting, no pre-mixed fuel,
  • no flooding when flipping over the bike


The KTM 300 EXC has been a successful and winning bike over many years both in the Enduro World Championship and in Extreme Enduro races. For MY 2018, the EU model features a global first and genuine milestone in off-road 2-stroke history in the guise of the newly developed TPI fuel injection. With this new technology, the compact powerplant offers the strongest 2-stroke performance money can currently buy in the E3 class. The fuel injection makes the bike even more controllable and ner to ride, while at the same time drastically cutting down on fuel consumption and emissions. And there is definitely no off-road racing motorcycle with a better power-to-weight ratio. In a word: truly the start of a new era.

When it comes to optimal power-to-weight ratio and outstanding Enduro speci c performance, there is no way around the new KTM 300 EXC engine. It features an all new TPI electronic fuel injection system that will set a new benchmark in the off-road competition 2-stroke segment. And thanks to its modern architecture, including high-end features such as the well protected E-starter, a new cylinder with two injectors and exhaust control, a 6-speed Enduro transmission and a hydraulically operated DDS clutch, it will be the best choice when the going gets real tough.


  • Reduced fuel consumption
  • Automatic elevation compensation, no re-jetting required
  • Enhanced rideability and performance
  • Reduced emissions
  • Smooth engine behaviour
  • Reduced fuel evaporation, which also means less fuel smell in transport vehicles
  • Enhanced comfort and convenience: easy starting, no pre-mixed fuel,
  • no flooding when flipping over the bike