Motorcycle specifications KTM250 EXC TPI 2018 First injection

Already out of the ordinary with performance worthy of a more complex 4-stroke motorcycle, the KTM 250 EXC sets itself apart even further in 2018 by adopting a new electronic fuel injection system quite unique on a sporty 2-stroke. Riding a competition bike is like stepping into the ring. 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 taking it to the next level. The 2018 version of the KTM 250 EXC (European model only) introduces a new TPI (Transfer Port Injection) electronic fuel injection system, unique on a sporty 2-stroke. 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 that promote mass centralization, a perfectly protected electric starter, a balancer shaft to reduce vibrations, a special Enduro 6-speed gearbox and a hydraulic DDS clutch. Let yourself be stunned by the gentle symphony of a 2-stroke engine, and enjoy ultra-smooth, ultra-safe riding.

Cylinder
The cylinder of the KTM 250 EXC TPI, with a bore of 66.4 mm, 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 new 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 the air flow to the control unit. In addition, the engine's character can be altered in a matter of seconds by adjusting the two springs on the control shaft.

Oil pump
Owners of a KTM EXC TPI can now do without the traditional 2-stroke oil/petrol pre-mix. An electronic oil pump circulates oil from the oil tank to the engine, via the throttle valve 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 gasoline), enduro riders can rest easy for a long time to come.

Engine crankcases
For optimum mass centralization, KTM engineers have designed ultra-light molded crankcases 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 freed up space for the installation of a balance shaft. 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. Because even greasy terrain enthusiasts take a dim view of mud when it gets lodged in the wrong places.

Balancing 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, featuring a wear-free steel clutch housing, heat-resistant clutch plates and new 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.

Throttle body
The TPI fuel-injected engine features an all-new throttle body developed by Dell`Orto, with a diameter of 39 mm. The amount of air entering the engine is regulated by a throttle linked to a cam (with two cables) controlled by a new handlebar-mounted 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. The oil drawn by the oil pump passes through the intake pipe before being mixed with the incoming air to lubricate the crankshaft bearings, cylinder/piston, etc.

Exhaust system
This nickel-plated exhaust system is by WP Performance Systems. Based on the carburettor model and derived from 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.

Engine management system
The engine management system (EMS) on TPI models features a new 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.

Alternator
TPI models feature a more powerful generator capable of supplying 196 W (as much as on their 4-stroke EXC counterparts) to meet the power requirements of the engine management system. The new ECU is based on the EXC-F models.

Lightweight
Year after year, KTM engineers strive to make their bikes lighter. The result is clear: the 2018 KTM EXC models are among the lightest and sleekest motocross bikes on the market.

Air filter housing
The air filter housing has been designed to better protect the air filter from clogging and ensure optimum air flow. EXC TPI models inherit an air temperature sensor and a new intake snorkel designed specifically for the new throttle body. The cage housing the extra-large Twin Air air filter is totally rigid, helping to hold the system in place. The design is simple, allowing the filter to be replaced in seconds, without the use of tools.

Cooling system
KTM's proven integrated cooling system circulates coolant from the cylinder head via the frame triangle 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. The new radiator covers 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.

Battery and wiring harness
The starter motor is fitted 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.

Handlebars
This NEKEN handlebar, with its high-strength aluminum profile, is no exception to the rule. 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 rear-grip adjustment system. right: a vulcanized handle; left: the ODI lock-on handle, as comfortable as it is practical, thanks to its glue- and wire-free mounting system. All models can be retrofitted with a handlebar-mounted power curve switch, allowing you to change engine mapping to suit all conditions.

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

Wheels
Featuring ultra-light CNC-machined hubs and top-of-the-range Giant rims, EXC wheels guarantee maximum stability despite limited weight. And since they are shod with MAXXIS tires, the bike is just as comfortable and safe off-road as it is on the road.

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

Dress
KTM factory riders collaborated on the bike's design with KTM R&D specialists and the Kiska design agency, with a single watchword: to create perfect harmony between rider and machine. Particular attention was paid to ergonomics and contact points to enhance freedom of movement and comfort on the EXC TPI. The special shape of the front and rear mudguards guarantees maximum stability and minimum weight, thanks to a well thought-out structure and assembly. Best of all, they stay clean longer. The clever mounting of the brake hose on the cross front plate also reduces wear and tear.

Graphics
Last but not least, the new deco kit confirms the READY TO RACE character of the 2018 KTM EXC range.

News and media credits: KTM