01. Engine & Exhaust
Thanks to state-of-the-art engineering, innovative 2-stroke design and revolutionary TPI fuel injection technology, the 150 cc 2-stroke powerplant is more refined than ever before, delivering class-leading power throughout the entire rev range. The benefit to this compact, lightweight 2-stroke, is reflected in the highly effective power delivery and easy rideability, making it a great option for those looking to delve into more extreme enduro action. With Euro IV homologation, it's not only considerately green, but leaves the competition green with envy too.
The KTM 150 EXC TPI cylinder has a bore of 58mm and with the aid of a sophisticated power valve, provides really 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 cylinder features a power valve unit with a sophisticated mechanism for the lateral support exhaust ports. 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 cylinder, with TPI technology, produces outstanding performance over the entire rev range with impressive torque. Last but not least, the cylinder allows for the use of a more widely available traditional type of spark plug.
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 EXC.
The KTM 150 EXC TPI is fitted with a robust 6-speed transmission made by PANKL Racing Systems. The gears are made of a strong, forged raw material, ensuring the highest durability and reliability level. This guarantees superior reliability. Another highlight of the 150 EXC TPI transmission, is the no-dirt gear shifter. Similar to the footpeg design, it prevents the build-up of dirt and ensures the next gear is always available, no matter what the conditions.
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 and 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. An optional map select switch can be purchased, which allows the rider to select an alternate map while on the fly, for the optimal power delivery no matter the conditions.
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, bigger smiles.
The 150 EXC TPI is fitted with a DS (diaphragm steel) clutch. It features a one-piece clutch basket and primary gear made of high-strength billet steel. Its compact rivet-less design guarantees unbeatable reliability. The clutch is fitted with extremely heat-resistant steel carrier friction discs which ensure excellent disengagement of the clutch and are pre-tensioned by means of a diaphragm spring, substantially reducing the lever force required by the Brembo hydraulic system.
Pre-mixing 2-stroke fuel is a thing of the past for KTM EXC TPI owners. The 2-stroke range is fitted with an oil tank featuring flexible mountings, which greatly improve durability and reliability. In addition, a mesh filter helps prevent dirt getting into the oil pump. Mounted below the oil tank, the oil pump delivers the lubricant directly to the throttle body, where it is mixed with the incoming air to lubricate the piston and crankshaft. Using engine speed and throttle position sensor data, the engine management's precise electronic control of the oil pump ensures that the ideal amount of oil for any given conditions is used. The filler cap assembly for the oil tank is located between the fuel tank and steering head, utilizing a hose in the upper frame tube to transfer the oil to the storage container. With an average fuel-to-oil ratio of 1:80, the oil capacity of about 0.7 liters is sufficient for at least five tanks of fuel.
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. The idle system allows the idle speed to be set more precisely via the bypass screw. Also, the cold start system provides a better supply of extra air when opening a bypass. Oil supplied by the electronically controlled oil pump via an oil intake tube is mixed with the incoming air to lubricate the moving engine parts.
To accommodate the power requirements of the engine management system, the TPI models are fitted with a powerful 196 W alternator and a voltage regulator. The same as can be found on the EXC-F 4-stroke models.
Maintaining the optimal engine temperature is crucial to ensuring consistent horsepower throughout the ride. The KTM 150 EXC 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. By using CFD technology (computational fluid dynamics) together with a clever coolant circuit routing, the innovative system ensures the optimum engine temperature for the highest performance, no matter what the conditions. Above all, the delta distributor, integrated into the frame triangle, features a large center tube, making the coolant flow from the cylinder head to the radiators highly efficient. The radiators also feature special protectors that don't only serve as protection from flying rocks and debris but also as a brace that disperses energy around the radiators in the event of an impact.
When it comes to power delivery and performance, the new exhaust plays a key role and packs a punch that is hard to beat. The pipe is produced with the latest 3-D stamping technology and has an optimized shape. It works perfectly with the TPI engine, producing excellent enduro-specific performance with impressive bottom end power. 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, a perforated inner silencer tube works with lighter damping material for efficient and durable noise reduction.