Motorcycle specifications KTM250 EXC TPI 2019 First injection

With its TPI injection system, KTM has given 2-stroke enduro machines a new future. In this world, the KTM 250 EXC TPI is not in the same league as its equal-weight rivals. Confident in its strength, it's even ready to take on more complex 4-stroke bikes. Muscular and weightless, this fuel-injected 2-stroke impresses with its sleek silhouette and lively performance.

muffler

kTM's 250 cm3 engine has long had the reputation of being the most powerful and competitive 2-stroke in its class. That hasn't stopped KTM engineers from improving it. The KTM 250 EXC TPI introduces an electronic TPI (Transfer Port Injection) injection system, the only one of its kind on a 2-stroke racing bike. This patented system (with two injectors mounted on the cylinder transfers) makes the engine much smoother and more fuel-efficient, which is no mean feat in technological terms. The KTM 250 cm³ engine has also benefited from a number of improvements: modern shaft assemblies to centralize mass, a perfectly protected electric starter, a balancer shaft to reduce vibrations, a special 6-speed Enduro gearbox and a hydraulic DDS clutch. The result is the sweet symphony of a 2-stroke engine, and an ultra-smooth, ultra-safe ride.

cylinder

the KTM 250 EXC TPI's 66.4 mm-bore cylinder features a sophisticated control spindle for smooth power delivery. The injectors responsible for introducing fuel into the rear transfers are positioned on either side of the cylinder. Combustion is therefore more efficient, resulting in fuel savings and lower emissions. A small tube at the rear of the cylinder is connected to the intake pressure sensor, which communicates air flow to the control unit.

engine crankcases and covers

for optimum mass centralization, KTM engineers have designed ultra-light, molded crankcases and raised the position of the vane.and raised the position of the crankshaft and clutch shaft to bring them closer to the center of gravity, resulting in exceptional handling. This trick also frees up space for a balance shaft, so you can swallow up the miles at full speed and in complete relaxation. Another interesting innovation to keep the engine as radiant as in the early days: crankcase covers with an elaborate surface structure designed to reduce wear caused by the rider's boots.

gearbox

the 6-speed gearbox, stepped especially for Enduro, is a model of precision and smoothness. As safety is also an essential parameter, the selector adopts a new "zero dirt" design that prevents the lever joint from jamming due to dirt. After all, even greasy terrain enthusiasts take a dim view of mud when it gets lodged in the wrong places.

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. The precise amount of fuel to be injected depends on sensor readings such as ambient and intake air pressure, throttle position and oil and water temperature. As the system is designed to compensate for altitude and temperature fluctuations, injection requires no manual intervention by the pilot.

balancer shaft

Numb hands and feet are not inevitable. The engine's design has made it possible to use a side-mounted balancer shaft that helps minimize vibrations. Driving is more comfortable and less tiring.

clutch

the KTM 250 EXC TPI uses a DDS (Damped Diaphragm Steel) clutch developed by KTM. a wear-free steel clutch housing, heat-resistant clutch plates and nitrate-treated steel liners. This clever design is distinguished by the use of a diaphragm spring instead of the usual coil springs, giving the clutch greater flexibility. The diaphragm spring also leaves plenty of room for a damping system integrated into the clutch hub, to enhance traction and durability. The clutch is activated by a hydraulic system manufactured by Brembo, which plays an essential role in the clutch's progressiveness and flexibility.

oil pump

the lucky owners of a KTM EXC TPI will now be able to do without the traditional 2-stroke oil-fuel pre-mix. An electronic oil pump circulates oil from the oil tank to the engine, via the throttle body, to ensure a perfect oil-fuel mixture, whatever the conditions and engine speed. The device, designed to reduce exhaust emissions by up to 50% compared with previous models, is controlled by the control unit according to engine speed and load, as measured by the throttle valve position sensor. With an oil capacity of 0.7 liters (enough for 5 to 6 full tanks of fuel), you'll have peace of mind for a long time to come.

injection unit

the TPI engine features a 39 mm throttle body developed by Dell`Orto. The amount of air entering the engine is regulated by a throttle linked to a cam (with two cables) controlled by the handlebar throttle. In addition, a throttle valve position sensor communicates air flow to the control unit, while idle speed is managed by the bypass screw. The cold-start device opens a bypass circuit to supply the extra air needed for cold starts. Oil drawn by the oil pump passes through the intake pipe before being mixed with incoming air to lubricate the crankshaft bearings, cylinder/piston, etc.

cooling

kTM's proven integrated cooling system circulates coolant from the cylinder head via the frame wishbone to the aluminum radiators supplied by WP. The additional KTM PowerParts cooling fan that can be added to this fuel-injected 2-stroke is now managed by the control unit, eliminating the need for a thermocontact. Its incredible efficiency is due to improved management of internal airflow and advances in ventilation thanks to CFD (Computational Fluid Dynamics) calculations. Radiator guards offer the advantage of better heat dissipation. This is all the more true in the presence of mud. Integrated into the front spoilers, these radiator guards are particularly useful in the event of an impact.

muffler

this nickel-coated muffler is by WP Performance Systems. The result of modern 3D production processes that give it remarkable precision and reliability, this muffler has been designed to exploit the full operating range and maximum power of the engine.

chassis

year after year, KTM engineers strive to make their bikes lighter. The result is clear: the 2019 KTM EXC models are among the lightest and sleekest motocross bikes on the market.

frame

the high-tech chromium-molybdenum steel frame is a model of lightness, flexibility and handling.the high-tech chromium-molybdenum steel frame is a model of lightness, flexibility and handling, offering excellent stability and diabolical precision when cornering. Thanks to its high torsional stiffness and low longitudinal rigidity, this frame better absorbs the energy generated by the front and rear suspensions when jumping or negotiating a bump. The ride is more comfortable and less tiring. The dropouts that link the cylinder head to the frame are as light as ever. Mounted laterally, they help limit vibration levels. Two threaded inserts have been provided in the lower cradle tubes to add a shoe, should the need arise. The engineers can be proud of their work, as the frame is now one kilo lighter than the lightest competing frame on the market today. Every effort has also been made to facilitate maintenance and free up space for the fuel tank and other components. On EXC TPI models, the fuel filler cap at the top of the frame feeds the oil tank via a hose inside the frame tube. The ultra-light buckle, made of stable aluminum profiles, weighs in at less than 900 grams.

swingarm

in addition to weight savings, cast aluminum is ideal for bending. The one-piece molding process eliminates the imperfections inherent in welding, guaranteeing a more homogeneous, but also more meticulous, manufacturing quality.

wheels

when it comes to wheels, KTM engineers know their stuff. Featuring ultra-light CNC-machined hubs and top-of-the-range Giant rims, the EXC's wheels guarantee maximum stability despite limited weight. And because they're shod with MAXXIS tires, the bike is just as comfortable and safe off-road as it is on.

front suspension

the WP XPlor 48 upside-down fork is a fork with separate damping circuits, developed by WP in close collaboration with KTM. Each fork arm has its own spring, and each has a different function: the left arm handles compression damping, while the right arm handles rebound. To fine-tune each of these settings, simply turn the knob at the top of the fork. To limit the risk of bottoming, the fork is equipped with a watertight hydraulic stop. High-quality materials, an ultra-sophisticated production process, 300 mm of travel: nothing has been left to chance to make the WP XPlor 48 fork the ultimate in responsiveness and damping. The preload ring (available as retrofit) allows easy adjustment of spring preload to three levels (standard, +3 mm, +6 mm), without the need for tools.

rear suspension

a true KTM trademark, the PDS shock absorber is connected directly to the upper part of the swingarm. As a result, engineers were able to mount it in the most appropriate position for even more progressive damping. As the shock absorber has been moved closer to the central axis, the loads exerted on the swingarm and frame are virtually symmetrical. This also frees up space for the exhaust system. The second piston, combined with a cup-shaped limit stop (instead of a needle-type one) and supported by a progressive-action spring, guarantees excellent resistance to bottoming. With its various machined and anodized components and its characteristic WP color scheme, this ultra-sophisticated shock absorber makes a strong impression compared to less well finished competing products.

fork tees

forged fork crowns with a 22 mm offset provide better fork support and even more precise front-end behavior. The EXC TPI offers four positions for moving the handlebars forwards or backwards, for a perfect grip.

brakes

these little jewels of technology are combined with Wave brake discs renowned for their lightness. More responsive, more efficient and more powerful than ever, Brembo brakes are ready for any situation.

fuel tank

the ultra-light polyethylene fuel tank has a capacity of 9.25 liters. EXC TPI models feature an integrated fuel pump system and an additional, practical fuel level indicator to prevent running out of fuel.

air filter housing

the air filter housing has been designed to protect the air filter from clogging and ensure optimum air flow. The cage housing the extra-large Twin Air air filter is totally rigid, helping to hold the system in place.

handlebars

when it comes to handlebars, KTM engineers have always known which way to go. This NEKEN handlebar, with its high-strength aluminum profile, is no exception. It features a throttle control (with two cables for EXC TPI models, as for their 4-stroke counterparts), a new double-cable aluminum handlebar, and an ultra-simple guard adjustment system. right: a vulcanized handle; left: the ODI lock-on handle, as comfortable as it is practical, thanks to its glueless, wire-free mounting system. All models can be fitted with a handlebar-mounted ignition curve selector (retrofit) to change engine mapping.

footrests

sophisticated "zero-dirt" footrests prevent the gear selector from getting dirty, even when passing through deep ruts. To enhance ground clearance, the gear selector on Enduro models is 6 mm higher than on SX models.

battery and wiring harness

the starter motor is combined with a powerful lithium-ion battery, which saves a considerable amount of weight compared to before. The battery and wiring harness are grouped together in a compartment above the air-filter housing, to avoid interference with the electrical circuit when removing the buckle. Mechanics and do-it-yourselfers will appreciate this.

News and media credits: KTM