01. Engine & Exhaust

Engine
The 300 cc 2-stroke engine has plenty of 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 2020 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. With Euro IV homologation, it's not only considerately green, but leaves the competition green with envy too.


Cylinder
The cylinder ON THE KTM 300 EXC TPI SIX DAYS has a bore of 78 mm and is fitted with a sophisticated power valve, which 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 for less emissions, a more efficient combustion and reduced fuel consumption. A little tube in the back of the cylinder is connected with an intake pressure sensor, which supplies pressure data to the control unit. As of the 2020 model, the cylinders feature an improved power valve unit with a sophisticated mechanism for the lateral support exhaust ports. The new exhaust port layout increases engine performance, while the upper contour of the exhaust port has been machined to ensure more accurate port timing. Last but not least the new models allow the use of a more widely available type of traditional 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. Plus, 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.


Transmission
The KTM 300 EXC TPI is now fitted with a new, more robust 6-speed transmission made by PANKL RACING SYSTEMS. The gear ratios were carried over from the predecessor, but is now made of a stronger, forged raw material, ensuring the highest durability and reliability level. Another highlight of the 300 EXC TPI ERZBERGRODEO 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.


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, bigger smiles.


Clutch
The KTM 300 EXC TPI SIX DAYS employs the KTM-developed DDS clutch (damped diaphragm steel) with a wear-free steel basket, extremely heat resistant clutch plates and nitrated steel liners. 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 without compromising durability. Light operation and a 'telepathic' level of control come standard with this hydraulic Brembo actuated clutch.


Oil pump
Pre-mixing 2-stroke fuel is a thing of the past for KTM EXC TPI owners. The 2020 models are fitted with a newly designed 2-stroke oil tank featuring reworked and more 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.


Throttle body
The TPI engine is fitted with a redesigned 39mm 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. For MY20 the idle system was reworked allowing the idle speed to be set more precisely via the bypass screw. Also, the cold start system is improved for 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.

TPI ALTERNATOR
To accommodate the power requirements of the upgraded 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.

Cooling
Maintaining the optimal engine temperature is crucial to ensuring consistent horsepower throughout the ride. The KTM 300 EXC TPI SIX DAYS features newly designed radiators which are mounted 12 mm lower than the predecessors. This lowers the center of gravity and matches the design of the new 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, a reworked delta distributor, integrated into the frame triangle, features a 4 mm larger center tube, increasing the cross section by 57%, making the coolant flow from the cylinder head to the radiators more 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.


Exhaust
When it comes to improved power delivery and performance, the new exhaust plays a key role and packs a punch that is hard to beat. The 250 cc and 300 cc models feature new HD exhaust pipes (heavy-duty) made by using an innovative 3D stamping process which produces a ripped surface finish. This makes the pipe much stronger, with better resistance against rocks, while also helping to reduce noise drastically. The silencer features a new shape and end cap with reworked internal designs individually developed for each model. The plastic silencer holder is now replaced with lightweight, welded mounting brackets. In addition, the exhaust's new shape provides slimmer ergonomics and more ground clearance, while a new perforated inner silencer tube works with lighter damping wool for more efficient and more durable noise reduction. This adds up to a weight reduction of approximately 200 grams. The silencer on this model also displays the Sixdays logo for further distinction from the crowd.

CNC-parts