01. Engine & Exhaust

Engine
Compact dimensions with an unbelievable power output, the KTM 350 XCF-W's fuel-injected DOHC engine offers the best power-to-weight ratio on the market, thanks to newly developed camshafts, exhaust system and updated electronic fuel injection. Its class-leading power delivery is available throughout the entire rev range. The weight is reduced to 61.7 lbs (28 kg), making it almost as light as a 250, while offering power and torque closer to a 450 cc.


Cylinder head
The KTM 350 XCF-W has a reworked cylinder head design with a similar architecture as the 2019 KTM 350 EXC-F, but is now 200 gr lighter. The 2 new overhead camshafts and flow optimized ports guarantee outstanding, offroad-specific engine characteristics. The DLC coated finger followers, as well as the lightweight valves they actuate (intake 36.3 mm, exhaust 29.1 mm), allow for higher engine speeds, a crucial factor in the 350's dynamic performance. The new head also features a new cylinder head cover and gasket, as well as a new spark plug and spark plug connector.


Crankshaft
The KTM 350 XCF-W's crankshaft is located in an ideal position close to the center of gravity, contributing to easier handling. It utilizes a short connecting rod, which makes for an overall compact and lightweight engine with a snappy power delivery. A plain big (bottom) end bearing with two force-fitted bearing shells runs directly on the crank pin. The engine's pressurized lubrication system provides the necessary oil feed for this bearing. This design has a direct benefit for the crankshaft with extended service intervals, which are lengthened due to the plain bearing. So just pin it, all day long.


Engine cases and covers
The XCF-W models feature reworked engine cases, reducing the weight by nearly 300 gr. The design allows for a very centralized shaft configuration, making the engine very short and compact, while contributing to an efficient centralization of mass. Additionally, 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 it.


Transmission
The 350 XCF-W uses a new 6-speed transmission made by PANKL RACING SYSTEMS, that now features a stronger, forged raw material, ensuring the highest durability and reliability. There was no need to change the gear ratios that are perfectly matched to the power characteristics of the engine. All four-stroke engines are fitted with a gear sensor, giving the option of different engine characteristics for each gear.


Engine management system
The state-of-the-art Keihin Engine Management System, with electronic fuel injection, features a new 42 mm throttle body. There are separate systems for cold starting and idle adjustment, while an improved seal of the MAP sensor (MAP = Manifold-Absolute-Pressure) makes the system even more reliable. A reworked throttle cable mount allows for easy access and smoother routing of the cables. Additionally, for 2020, the ECU features new maps which have been adapted to the new exhaust, airbox and engine configuration, regulating the unique traction control and are activated by a map-select switch. It also provides different maps for each gear, according to the information received from the gear sensor, ensuring maximum power as you shift through the gears.


Cylinder and piston
The new, extremely short 88 mm bore cylinder features a reworked cooling concept that works together with the new, forged bridged box-type piston made by CP. The piston crown geometry has been adapted to suit the high-compression combustion chamber. Despite its incredibly low weight, it has an extra rigid structure for enhanced durability. Thanks to its lightweight construction, the oscillating masses are low, giving the engine extremely lively characteristics. To further improve engine performance, the compression ratio has been increased from 12.3 to 13.5:1.


Balancer shaft
The multifunctional side-mounted counter balance shaft masterfully balances all the oscillating forces, while also driving the water pump. It effectively keeps engine vibrations to a minimum, resulting in the smoothest ride even at the highest engine speeds.


Clutch
The KTM 350 XCF-W is fitted with the extremely durable, KTM-developed DDS clutch (damped diaphragm steel), with a wear-free steel basket and heat resistant clutch plates. It uses a diaphragm spring instead of the usual coil springs, which results in considerably easier clutch action. The diaphragm spring is also compact enough to allow for a damping system to be integrated into the clutch hub, contributing to better traction and durability. Additionally, the Brembo hydraulic system provides easy and precise clutch modulation throughout the entire operating temperature range.


E-Starter
The standard electric starter on the KTM 350 XCF-W uses a proven starter drive and a strong starter motor made by Mitsuba. As demonstrated time and time again, it provides quick and reliable starting, saving you precious time and energy when you need it most.


Cooling
Maintaining the optimal engine temperature and consistent horsepower throughout the ride, the KTM XCF-W range features newly designed radiators which are mounted 12 mm lower than the predecessors, lowering the center of gravity, matching the design of the new shrouds perfectly and providing perfect ergonomics. By using CFD technology (Computational Fluid Dynamics) and a smarter coolant circuit routing, the innovative system ensures optimum engine temperature for the highest performance, in all conditions. Above all, a reworked delta distributor, integrated into the frame triangle has a 4 mm larger center tube, increasing the cross section by 57%, so coolant flows from the cylinder head to the radiators more efficiently. The radiators have special protectors that protect from flying rocks and debris while also acting as a brace to disperse 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. All 4-stroke XCF-W models feature new, two-piece header pipes (two parts instead of one on the predecessor) which can now be disassembled much more easily and which allows better access to the shock. The aluminum muffler sleeve has a newly designed, slightly larger profile with a new end cap. Compared to the predecessors they are shorter and more compact, bringing the weight closer to the center of gravity for better mass centralization.
