01. Engine & Exhaust

Engine
Featuring a compact and lightweight (60 lbs) construction, this DOHC (double overhead camshaft) design boasts lightweight titanium valves and Diamond-like Coating (DLC) cam followers allow for lively power across the rev range. As the 350 cc motor shares much of its design with the 250 cc 4-stroke mill, the KTM 350 XC-F has managed to pump out big power, but remain as nimble as a smaller machine, making it the perfect middleweight monster.


Cylinder head
The cylinder head features two overhead camshafts with friction-optimized cam followers boasting a DLC coating and high-flow ports. Four lightweight titanium valves maximize the flow rate for an optimal power band and outstanding performance across the seemingly endless rev range of 13,400rpm. Lateral brackets made of aluminum allow an efficient fixation of the engine to the frame and contribute to the bike’s featherweight feel.


Crankshaft
The KTM 350 XC-F's crankshaft 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 necessary oil feed for this bearing is ensured by the engine's pressurized lubrication. This design is a decisive benefit in terms of the crankshaft service interval, which can be lengthened due to the plain bearing. So just pin it, all day long.


Crankcases and engine covers
The design of the die-cast crankcases allows for minimal weight and a very centralized shaft configuration. This makes the engine short and compact, while contributing to an efficient centralization of masses. The engine covers also feature a solid surface structure, which reduces the wear caused by the rider’s boots. This way, your SX-F will keep looking better longer.


Transmission
The KTM 350 XC-F features a robust 6-speed transmission made by PANKL Racing Systems. The gears are made of a strong, forged raw material and feature a special surface treatment on the 2nd, 3rd and 4th gear, ensuring the highest durability and reliability level. An advanced ´No Dirt´ gear shift lever design prevents mud and sand from blocking the joint of the lever and guarantees trouble-free shifting. All 4-stroke engines are fitted with a gear position 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 44 mm throttle body with separate systems for cold starting and idle adjustment. The throttle cable mount allows for easy access and a smooth routing of the cables. The ECU features selectable engine maps which are optimized to the exhaust, airbox and engine configuration, as well as regulating the unique traction control and launch control which are activated by the handlebar 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
Inside the short 88 mm bore cylinder, is an extremely lightweight, forged bridged box-type piston made by CP. Its crown geometry is adapted perfectly to the high-compression combustion chamber (14:1), where its rigid structure and low weight shine. Thanks to the low oscillating masses, the engine is both snappy and strong.


Balancer shaft
To balance the mass-forces, the KTM 350 SX-F engine uses a multifunctional balancer shaft, which at the same time drives the water pump and timing chain.


Clutch
The KTM 350 XC-F is fitted with the extremely durable, KTM-developed DS clutch (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. 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 XC-F 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 is crucial to ensuring consistent horsepower throughout the ride. The KTM 350 XC-F 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) and a smart coolant circuit routing, the innovative system ensures optimum engine temperature for the highest performance, in all 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 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 power delivery and performance, the exhaust on all 4-stroke models plays a key role and packs a punch that is hard to beat. It features a model specific header pipe with an advanced resonator called FDH (Flow Design Header), which is a small chamber around the pipe. The design allows the exhaust to be disassembled without removing the shock absorber and also provides better access to the shock. The aluminum sleeve, end cap and internal design of the silencer allows for slimmer ergonomics, making the bike feel narrower, without compromise to regulatory noise limits.
