Engine & Exhaust

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.

Cylinder

This compact cylinder with a 66.4 mm bore and with refined port timings and the aid of a sophisticated power valve, provides smooth and controllable power characteristics. For the EFI application the cylinder features two lateral domes which hold the fuel injectors that supply fuel to the rear transfer ports. The downstream injection guarantees excellent atomization of the fuel with the upstreaming air. Thus, the loss of unburnt fuel is minimal, resulting in less emissions, a more efficient combustion and reduced fuel consumption. A small tube in the back of the cylinder is connected with an intake pressure sensor, which supplies pressure data to the control unit. The exhaust port layout increases engine performance, while the upper contour of the exhaust port has been machined to ensure more accurate port timing. The new cylinder, with TPI technology, produces outstanding performance over the entire range with significantly increased torque compared to its predecessor.

Crankcases and engine covers

The compact engine cases are manufactured using a high pressure die-cast production process which helps with weight reduction, while retaining strength and durability. The design allows for optimal shaft arrangements close to the center of gravity, resulting in ideal mass centralization and easier ride-ability. The engine covers feature a smart surface structure which reduces wear caused by the rider’s boots, keeping them looking as fresh as the day you bought your XC TPI.

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.

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.

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.