01. Engine & Exhaust

Engine
The 250cc 2-stroke engine has plenty power and torque, but remains light enough for riders to muscle their way through the toughest obstacles. Thanks to state-of-the-art engineering, innovative 2-stroke design and revolutionary TPI fuel injection technology, the powerplant is even more refined than ever before. The compact and lightweight 2-stroke is a great choice for offroad riders who want usable enduro performance that is ready to conquer in the most extreme terrain.


Cylinder
The KTM 250 XC TPI cylinder has a bore of 66.4mm and is fitted with a state-of-the-art power valve providing smooth and controllable power characteristics. For the EFI application the new cylinder features two lateral domes, which hold the fuel injectors supplying fuel into the rear transfer ports. Thus the loss of unburnt fuel is reduced for less emissions, a more efficient combustion and reduced fuel consumption. A tube in the back of the cylinder is connected with an intake pressure sensor, which supplies pressure data to the control unit.


Crankcases and engine covers
These die-cast crankcases allow the implementation of a balancer shaft. So your ride will be as relaxed as it is rapid. Plus, your new favorite engine will keep looking as fresh as the day you bought it: its engine covers feature a smart surface structure in order to reduce the wear caused by the rider’s boots.


Transmission
The robust 6-speed transmission made by PANKL Racing Systems features an Enduro-specific wide-ratio specification and provides precise and easy shifting. An advanced ´No Dirt´ gear shift lever design prevents mud and dirt from blocking the joint. Because even dirt lovers hate mud when it's in the wrong places.


Balancer shaft
Say goodbye to numb feet and hands. This engine design allows the implementation of a lateral balancer shaft in order to keep the vibrations to a minimum. You know what that means: more comfort, less fatigue, more racing.


Clutch
The KTM 250 XC TPI employs the KTM-developed DDS clutch (damped diaphragm steel) with a robust steel basket, extremely heat resistant clutch plates and new, nitrated steel liners reducing the wear. 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. Light operation and telepathic amounts of control are standard with this hydraulic Brembo actuated clutch.


Throttle body
The TPI engine is fitted with a 39 mm throttle body made by Dell`Orto. The airflow is regulated by a butterfly connected with a twin-cable throttle cam, which is operated by the handlebar throttle assembly. A throttle position sensor provides airflow data to the control unit, while a bypass screw allows the regulation of the idle speed. The cold start device also opens a bypass supplying more air. Via an oil intake tube oil supplied from the oil pump is mixed with the incoming air to lubricate crankshaft bearings and cylinder/piston etc.


Engine management system
The engine management system (EMS) of the TPI models features a control unit located below the seat. The ECU defines the ignition timing while the amount of fuel to inject is based on several sensor readings such as intake air pressure, throttle position and water temperature plus a new additional ambient air pressure sensor. Thanks to altitude and temperature compensation the rider does not need to worry about fiddling around with the jetting anymore. Should the rider decide to mount a radiator fan from the KTM PowerParts program, it will be controlled directly by the EMS without needing to add an additional thermal switch.


Cooling
Maintaining the optimal engine temperature is crucial to ensuring consistent horsepower throughout the ride. The KTM 300 XC-W TPI features radiators which are mounted close to the center of gravity and match the design of the shrouds perfectly, in order to achieve perfect ergonomics. The additional KTM PowerParts radiator fan is regulated by the EMS control unit for easy installation. Thanks to flow optimized internal circulation and CFD-calculated ventilation, the system is superbly efficient. In addition the radiator protectors improve heat dissipation. Especially in the mud. They are also integrated into the front part of the shrouds to protect the radiators in a crash.


Exhaust
When it comes to power delivery and performance, the exhaust plays a key role and packs a punch that is hard to beat. The 250 cc and 300 cc models feature HD exhaust pipes (heavy-duty) made by using an innovative 3D stamping process which produces a ribbed surface finish. This makes the pipe much stronger, with better resistance against rocks, while also helping to reduce noise drastically. The silencer features a compact shape and end cap with internal designs individually developed for each model, while it is mounted using an aluminum mounting bracket. In addition, the exhaust's shape provides slim ergonomics and more ground clearance, while a perforated inner silencer tube works with lighter damping material for efficient and durable noise reduction.
