01. Engine & Exhaust

Engine
The 450 XC-F features the same compact 450 cc powerhouse as in the ripper 450 SX-F. KTM's engineers worked tirelessly to increase the READY TO RACE ability of this machine by including the latest engine management technology and refining the SOHC cylinder head and the latest electronic fuel injection. This means the 450 XC-F pumps out unrivaled horsepower with one simple goal in mind - to win races!


Cylinder head
Inside the SOHC cylinder head, an overhead camshaft controls four ultra-lightweight titanium valves via extremely rigid rocker arms, which are DLC-coated on the intake side. A configuration like this allows engine speeds of up to 11,500 RPM; a baffling figure for a large displacement thumper. 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 450 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 XC-F will keep looking better longer.


Transmission
The KTM 450 XC-F uses a lightweight 5-speed transmission with gear ratios that are perfectly matched to the power delivery of its large displacement engine. The 1st and 3rd gears are treated with a special surface coating for better reliability. 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. Thanks to its unique injector position, the engine's response is instantaneous. And to make life even easier, separate systems for cold starts and idle adjustment await you. The lightweight control unit features a unique traction and launch control system for lightning-quick response when the gate drops and maximum grip thanks to different maps that sync with the gear you're in. It's also possible to unleash an even more powerful mapping via the handlebar map select switch.


Cylinder and piston
Inside the short cylinder, with a bore of 95 mm, thumps a new box-type piston made by CP with a reworked shape for improved performance. Its crown geometry is adapted perfectly to the high-compression combustion chamber, where its rigid structure and low weight shine. Thanks to the low oscillating masses, the engine is as snappy as it is strong.


Balancer shaft
The side-mounted balancer shaft does double duty also driving the water pump. Thanks to its perfect balance and low oscillating masses, engine vibration is kept to a minimum.


Clutch
The KTM 450 XC-F employs the KTM-developed DDS clutch (damped diaphragm steel) with a robust steel basket, extremely heat resistant clutch plates and 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.


E-Starter
Like all KTM 4-stroke motorcycles, the KTM 450 XC-F is started at the push of a button - a priceless advantage when you're on the clock.


Cooling
KTM's proven cooling system routes the coolant from the cylinder head through the frame triangle, directly to aluminum radiators. Thanks to flow optimized internal circulation and CFD-calculated ventilation, the system is superbly efficient. In addition, radiator protections improve heat dissipation. Especially in the mud. They are also integrated into the front part of the shrouds to protect the radiators from 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 allow for slimmer ergonomics, making the bike feel narrower, without compromise to regulatory noise limits.
