Motorcycle specifications KTM250 EXC TPI 2020 Goals to Achieve

Engine and Muffler

KTM’s extensive range of 2-stroke off-road competition motorcycles serves as a true showcase of the brand’s technology. Two years after introducing the world’s first 2-stroke off-road motorcycles to feature electronic fuel injection, KTM is once again making waves with a new generation of off-road competition engines equipped with a revolutionary TPI system. This demonstrates just how much KTM believes in the future of 2-stroke technology. The benefits are clear: in addition to significantly reducing fuel consumption and emissions, this system eliminates the need for fuel premixing and manual adjustments by the rider to fine-tune the bike’s fuel mixture. The engine can thus perform to its full potential under all conditions.

Cylinder

The 250 EXC TPI’s 72-mm-bore cylinder features a sophisticated exhaust valve control system that ensures smooth power delivery. The injectors responsible for delivering fuel into the rear porters are positioned on either side of the cylinder. Downward injection offers the advantage of ensuring excellent atomization with the rising air. Combustion is therefore more efficient, resulting in improved fuel economy and reduced emissions. A small tube at the rear of the cylinder is connected to the intake pressure sensor, which communicates the airflow to the control unit. The 2020 model features state-of-the-art exhaust valve control and a sophisticated mechanism for the side exhaust outlets. The new exhaust outlet configuration helps boost the engine’s performance. The upper contour of these components has even been machined to ensure ultra-precise alignment. Last but not least, the new models allow for the use of a more common type of spark plug.

Engine Cases and Covers

The use of high-pressure die-casting results in a relatively compact and even lighter engine case, while maintaining its strength and durability. The crankcase design allowed KTM engineers to position the shaft mounts closer to the center of gravity, thereby better centralizing mass and enhancing riding comfort. Another interesting innovation to keep your EXC’s engine looking as good as new: engine crankcase covers with a sophisticated surface texture designed to reduce wear caused by the rider’s boots.

Gearbox

The 250 EXC TPI is now equipped with a new, more robust 6-speed gearbox manufactured by PANKL RACING SYSTEMS. The gear ratios from the previous version have been carried over. This gearbox is made of a stronger forged material, ensuring superior durability and reliability. The “zero-dirt” design of the gear selector is another highlight of the gearbox on the 250 EXC TPI. Designed on the same principle as the footrest, it prevents dust buildup and keeps the gearbox operational in all conditions.

Engine Management

The engine management system (EMS) on TPI models features a control unit located under the seat. Ignition timing is calculated by the control unit (ECU). The precise amount of fuel to be injected depends on measurements taken by sensors, such as intake air pressure, throttle position, and coolant temperature. Ambient air pressure is also taken into account. Since the system is designed to compensate for changes in altitude and temperature, fuel injection requires no manual intervention by the rider. Should the rider decide to install a cooling fan (available in the KTM PowerParts catalog), it would be placed under the direct control of the engine management system (EMS) without the need for an additional temperature sensor. An optional map selector can be purchased to switch engine modes on the fly and adapt power delivery to the conditions.

Balancing shaft

Numb hands or feet are not inevitable. The engine’s design allows for the use of a lateral balance shaft, which helps minimize vibrations. Riding is more comfortable and less tiring.

Clutch

The 250 EXC TPI uses a DDS (Damped Diaphragm Steel) clutch developed by KTM; it features a wear-resistant steel clutch bell, clutch plates with very high heat resistance, and nitride-treated steel sleeves. This clever design stands out for its use of a diaphragm spring instead of the usual coil springs, giving the clutch greater smoothness. The diaphragm spring also leaves enough room for a damping system integrated into the clutch hub, thereby promoting traction without compromising durability. The clutch is actuated by a hydraulic system manufactured by Brembo, which plays a key role in the clutch’s progressive and smooth operation.

Oil Pump

Happy owners of an EXC TPI can now do without the traditional oil-fuel premix typical of 2-stroke engines. The 2-stroke oil reservoir has been redesigned on the 2020 models. The mounting system is more flexible than before to further enhance durability and reliability. A filter has also been added to prevent contaminants from entering the oil pump. The oil drawn by the oil pump (mounted beneath the oil reservoir) flows through the injection body, where it is mixed with the incoming air to lubricate the piston and crankshaft. Based on engine speed and data from the throttle position sensor, the electronic control unit (ECU) of the engine management system (EMS) determines the optimal amount of oil to use under current conditions. The oil reservoir filler cap, located between the fuel tank and the steering column, allows the oil reservoir to be filled via a hose in the upper part of the frame tube. With an average fuel-to-oil ratio of 1:80, the reservoir has sufficient capacity (0.7 liters) for at least five full tanks of fuel.

Carburetor

The TPI fuel-injected engine is equipped with a new 39 mm carburetor developed by Dell'Orto. The amount of air entering the engine is regulated by a throttle valve connected to a cam (via two cables) controlled by the handlebar throttle. In addition, a throttle position sensor transmits the airflow to the control unit. On 2020 models, idle speed can be precisely adjusted using the bypass screw. The cold start system opens a bypass circuit to supply the extra fuel needed for cold starts. Oil supplied by the electronic oil pump flows through the intake pipe before being mixed with the incoming air to lubricate the engine’s moving parts.

TPI Alternator

To meet the power requirements of the new Engine Management System (EMS), TPI models are equipped with a voltage regulator and a generator capable of delivering 196 W (the same as on 4-stroke EXC-F models).

Cooling

To ensure smooth power delivery, maintaining optimal engine temperature is essential. To this end, the 250 EXC TPI features new radiators positioned 12 mm lower than on its predecessor. This positioning, perfectly adapted to the design of the new spoilers, lowers the center of gravity and enhances ergonomics. Thanks to computational fluid dynamics (CFD) and the carefully designed cooling circuit, this innovative system ensures that engine components are maintained at the ideal temperature to guarantee the highest level of performance, regardless of conditions. To ensure more efficient coolant circulation between the cylinder head and the radiators, the diameter of the central tube in the exhaust manifold (integrated into the frame triangle) has been increased by 4 mm, representing a 57% increase in flow cross-sectional area. The special guards fitted to the radiators not only protect them from flying stones and other debris, but also distribute the impact force of a collision around the radiators.

Muffler

The new exhaust system gives the engine a smoothness and responsiveness that are hard to match. The 250cc and 300cc models feature new, ultra-sturdy exhaust manifolds (with a flawless finish), achieved through an innovative 3D stamping process. These manifolds offer the advantage of better resistance to impacts from rocks and significantly reduced noise emissions. The muffler features a new shape and a new tip. The internal structure has been specifically modified for each model. The plastic mounting system for the muffler has been replaced by ultra-lightweight welded mounting brackets. The new shape of the exhaust system offers improved ergonomics and increased ground clearance. The use of a perforated inner tube and a lighter insulating material (rock wool) also helps improve the silencer’s efficiency and further reduce noise. The total weight savings amount to 200 grams.

Chassis

To be truly competitive, a 2-stroke enduro motorcycle must be lightweight. It is therefore no surprise that the 250 EXC TPI is among the lightest, slimmest, and most agile enduro motorcycles in its class.

Frame

All EXC models feature a new high-tech lightweight chromoly steel frame, constructed from hydroformed tubes assembled via automated welding. Engineers retained the competition-proven geometry but reworked certain parts of the frame to optimize stiffness. The ultimate goal was to improve rider feedback, agility, and stability. The mounting brackets connecting the cylinder head to the frame are now made of aluminum. Mounted laterally, they help reduce vibration and refine the bike’s handling in corners. The new side frame guards feature a textured surface for better grip. They also protect the rider from the heat emitted by the muffler on the right side. The engine of the 250 EXC has been lowered by 1° relative to the swingarm axis, significantly improving front-wheel traction. The rear subframe consists of ultra-lightweight and rigid aluminum profiles that are longer (40 mm longer) and lighter (900 g lighter) than before, designed to enhance the stability of the rear cowl.

Swingarm

The new one-piece aluminum swingarm on the 250 EXC TPI, produced via high-pressure die-casting, was designed to offer rock-solid strength while keeping weight to an absolute minimum. The one-piece casting process not only optimizes the material’s flex characteristics and weight but also allows for a wide range of geometries.

Wheels

Equipped with ultra-lightweight CNC-machined hubs and high-end GIANT rims, the wheels on all Enduro models ensure maximum stability despite their low weight. The aluminum spoke nuts on the 2020 models have been redesigned to reduce the frequency with which the spokes need to be retensioned.

Front Suspension

All EXC models feature the latest WP XPLOR USD fork with separate damping circuits (48 mm diameter), designed by WP and KTM. Although both fork legs are equipped with springs, their functions differ. The left leg handles compression damping, while the right leg handles rebound damping. To fine-tune each of these settings, simply turn the 30-click adjustment knob provided for this purpose above each fork leg. Although this fork is already renowned for its sensitivity and efficiency, it features a perfectly calibrated floating piston to make the damping even smoother on the 2020 model. Also worth noting are the new upper fork caps and new, more intuitive adjustment knobs, featuring new colors and graphics. The rider also benefits from new settings to raise the front end and thus increase resistance to bottoming out.

Rear Suspension

A key component of the proven PDS rear suspension, the WP XPLOR shock absorber is connected directly to the swingarm, eliminating the need for an additional linkage system. In addition to significant weight savings, this solution reduces the risk of snagging on large rocks. To ensure optimal progressive damping specific to enduro riding, a second piston is paired with a cup-shaped end-of-stroke stop and supported by a progressive spring. To enhance bottoming-out resistance without sacrificing comfort on the 2020 model, the second piston has been redesigned, and the sealing and shape of the end-of-stroke stop have been optimized. The new settings for the XPLOR PDS shock absorber, tailored to the specific characteristics of the new frame and front-end configuration, improve damping performance. Fully adjustable, including high-speed and low-speed compression, this shock absorber can be adapted to trail conditions or rider preferences.

Brakes

These Brembo brakes, true technological gems, are paired with Wave brake discs renowned for their lightness. Rarely has an off-road motorcycle offered such feel and braking efficiency.

Fuel Tank

All models in the EXC range feature a new, ultra-lightweight polyethylene fuel tank with improved ergonomics. The quarter-turn bayonet cap saves time when closing the tank. And since the cap is made of transparent plastic, a quick glance is all it takes to see how much fuel is left. This model is equipped with an integrated fuel pump system and a fuel level indicator. The 90-degree fuel line connection further protects the tank from damage.

Air Filter Housing

The air filter housing on the 250 EXC TPI has been completely redesigned to optimize airflow dynamics. Combined with the new intake snorkels, it ensures maximum power delivery and excellent acceleration. In addition to the obvious performance gains, the new design also serves to better protect the air filter from clogging. The rigid mount for the large Twin-Air air filter is designed to minimize installation errors. As with previous models, filter maintenance can be performed in record time and without tools—a unique feature typical of KTM.

Ergonomics and Comfort

KTM has drawn on its extensive experience and decades of racing success to refine the ergonomics of the 250 EXC TPI and create the perfect harmony between rider and machine. The rider thus enjoys complete freedom of movement and optimal comfort, regardless of conditions. The taillight has also been redesigned to match the new shape of the rear fairing and the motocross-style front license plate mount.

Handlebar

All EXC models are equipped with the same ultra-sturdy, profiled aluminum handlebar, manufactured by NEKEN. It can be adjusted to four different positions. On the right: an ODI vulcanized grip available as standard; on the left: an ODI lock-on grip that is as comfortable as it is practical, thanks to its mounting system that requires no glue or wire. Furthermore, all models can be equipped with a handlebar map selector (optional) to switch between Standard and Advanced power curves.

Seat

The seat on the 2020 EXC motorcycle range features a more ergonomic shape. It also benefits from even more comfortable foam padding. A long screw inserted on the side helps secure the seat to the motorcycle more effectively and makes handling it simpler and safer.

Bodywork and Graphics

The result of a collaborative effort between KTM factory riders, KTM R&D specialists, and the design agency Kiska GmbH, the bodywork of the 250 EXC TPI marks a new milestone in the evolution of the bikes. The shape of the bodywork on the Enduro range allows the rider to truly become one with the machine. The focus was primarily on the contact points to ensure complete freedom of movement for the rider and enhance maneuverability. The unique shape of the front and rear fairings ensures maximum stability with minimal weight. The taillight has been redesigned to match the new shape of the rear fairing and the front motocross plate holder. The new overmolded graphics underscore this bike’s sporting aspirations and the ambitions of the KTM brand.

Footrests

The sophisticated “zero-dirt” footpegs prevent the gear selector from getting clogged, even when riding through deep ruts. To improve ground clearance, the gear selector on the Enduro models has been raised by 6 mm compared to the SX models. But you’re free to change it if you feel like it.

Software and Electronics

The EXC TPI models feature one of the most advanced engine management systems ever developed for a 2-stroke enduro. Ignition timing is calculated by the engine control unit (ECU). The precise amount of fuel to be injected depends on measurements taken by sensors, such as ambient and intake air pressure, throttle position, and coolant temperature.

Battery and Wiring Harness

All engines are equipped with the proven electric starter, a major advantage off-road. To ensure the engine starts every time, the starter is powered by an ultra-light 2 Ah lithium-ion battery. The wiring harness has been optimized. Most electrical components are grouped under the seat for easy access and increased reliability.

Info and media credits: KTM