2017 KTM 450 SX-F
If gold is what you’re after, a 450 SX-F is what you get. Thanks to its compact engine delivering explosive but controllable power, it’s the weapon of choice for the Red Bull KTM Factory Team and their champ, Ryan Dungey. Ridden at its hardest, this bike is quick enough to rule the AMA Supercross Championship. Its secret? Sweet handling and gut-wrenching grunt. Winners, line up here.
The hugely successful 450 SX-F powerhouse has extremely compact dimensions, strong performance throughout the rev range and a low weight; this is the lightest 450 engine on the MX market. But that doesn’t mean it’s not a heavyweight in terms of muscle. Fitted with a single overhead camshaft cylinder head and the latest electronic fuel injection, it pumps out an unrivaled 62hp. With KTM’s engineers working tirelessly to increase service intervals, this super stroker has the latest engine management technology on board and confidently shoots both amateurs and pros to the top of their time sheets.
ENGINE MANAGEMENT SYSTEM
The state-of-the-art Keihin Engine Management System with electronic fuel injection features a 44mm 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 ECU features a unique traction and launch control system for lightning-quick response when the bar drops and maximized grip thanks to different maps that sync with to the gear you’re in. As an ultimate bonus, the rider can unleash an even more powerful mapping via the handlebar map switch.
The 450 SX-F employs the KTM-developed DDS clutch (damped diaphragm steel) with a wear-free steel basket and extremely heat resistant clutch plates. This clever design employs a diaphragm spring instead of the usual coil springs, which makes for a considerably easier clutch action. A diaphragm spring also leaves sufficient space for a damping system to be integrated into the clutch hub. The goal was traction, yes, but durability as well. On top of that, it is fitted with a lighter basket, a reworked inner hub and a pressure plate providing better oil supply and unsurpassed cooling. Of course, light operation and telepathic amounts of control are what makes this particular clutch, a hydraulic Brembo clutch.
The high-tech, lightweight chrome-moly steel frame has a knack for easy handling, outlandish rideability, precise cornering and excellent stability. You can also count on high torsional rigidity and low longitudinal stiffness. This results in better absorption of the energy created from the front and rear suspension, sucking up jumps and bumps. In short: more comfort and less rider fatigue. Laterally attached, lightweight aluminum engine head stays (the connection between cylinder head and frame) contribute to more precise cornering and a reduced vibration level. The engineers were able to pull off all that, while making their frame a big fat kilogram lighter than that of the lightest competitor on the market. In addition, it is easier to maintain, easier to work on and supplies more space for the tank and other components. The bike also features an extra-light subframe made of stable aluminum profiles, which tiptoes the scales at less than 900g.
FIM noise limits are a real challenge for every manufacturer. Therefore, KTM has put a lot of effort into the development of their exhaust systems. All 4-strokes are fitted with header pipes that have a unique standard feature; an additional resonator system – a small chamber connected to the pipe. For the 450 SX-F the engineers developed an even more advanced version called FDH (Flow Design Header) that provides better engine performance and reduced noise. Speaking of which: all 4-strokes are fitted with a short silencer, mounted as close to the engine as possible. You know what that means: extra mass centralization and better rideability. Its advanced internal design reduces the noise sufficiently in order to sit safely below the FIM noise limit (112 dB(A) at 2 meter max.), while still raising the hairs on your neck.
The cast aluminum design offers low weight and a perfect flex behavior. The single-component casting process eliminates any inconsistencies and inherent weak points created by welding. It’s better looking too.
Featuring lightweight, CNC machined hubs and high-end Excel rims, they guarantee maximum stability and minimal unsprung weight. The wheels are shod with the latest Dunlop Geomax MX 3S tires.
KTM’s proven cooling system routes the coolant from the cylinder head through the frame triangle, directly to aluminum radiators made by WP. Due to flow optimized internal circulation and CFD-calculated air ventilation, the system is superbly efficient. In addition, well thought-out radiator guards integrated in the front part of the spoilers provide protection in case of crashes.
The WP monoshock has been developed with the entire frame and swingarm architecture in mind, including the linkage system and the WP AER 48 front forks. It features machined and black anodized components and is a valuable, high-end product compared to roughcast reservoirs. A new setting and a softer spring perfectly match the reworked front-end set-up and its sparkling WP color scheme lets everyone know you have excellent taste in suspension.
The lightweight WP AER 48 front fork, a 48mm USD air-sprung fork developed by WP in close collaboration with KTM, is a split fork with separate functions for each leg. That means damping functions are on the right side, whereas the air spring is in the left. This left leg features a two-chamber system with a capsuled air cartridge to prevent loss of air pressure. Should the outer seal start to leak, the internal cartridge pressure will keep the bike in position. The air spring is easy to adjust to any rider weight via a single air valve. No special tools are required; the air pump supplied with the bike will do just fine. The right fork leg integrates a damping cartridge that tailors to all your damping needs. It can be adjusted to the track conditions and the rider’s preferences with a twist of a dial (compression from the top, rebound from the bottom, 30 clicks each). For MY2017, the AER 48 also features redesigned outer tubes with better bending characteristics, smoother operation and less friction. Plus: they’ve lost some weight (265g). Right off the dealer floor, these forks are more comfortable and more sensitive than ever. But you can still hammer the hell out of them.
Top quality, CNC machined triple clamps have been something of a KTM trademark for years. Ensuring a precise handling, they perceptibly support the flex characteristics, and with it the action of the forks. For MY2017, the upper triple clamp specifically features a redesign in conjunction with the new fork tubes. The rubber damped handlebar fixation has also been reworked and the lower handlebar clamps are now separated, while on the upper side a new bridge-type clamp guarantees more torsional stiffness and can easily be replaced in case it gets twisted due to a crash. In addition, an hour meter is fitted at the upper triple clamp in order to let the rider know it’s time for a service. Or a cold drink.
You couldn’t brake any harder, better, faster or stronger. These high-tech Brembo babies are combined with lightweight wave discs made by Galfer. For MY2017, the rear brake features a 10mm longer brake pedal and you get new, less aggressive brake pads all round.
HANDLEBAR MAP SWITCH
All 4-stroke models are equipped with a sophisticated new multi-functional handlebar map switch, which does three things:
· Activation of the traction control
· Activation of the launch control
· Selection of an alternative power curve (Standard or Advanced),
The traction control is a unique feature none of the competitors can offer so far. It guarantees more efficient traction and better control of the bike when accelerating. You’ll especially notice this on a rainy day. Push the button and reign supreme. With this map switch the rider can also activate the launch control, which provides more efficient starts out of the gate so you can go for the holeshot, time and time again. How? It simply reduces the maximum engine speed for the very first moment of the start, in order to give you better control. Push both buttons when the engine idles and the EFI control lamp mounted on the upper triple clamps will let you know your bomb is live. In addition, the map switch gives the rider the chance to select an alternative, more powerful map beside the standard configuration. Don’t you just love the idea of a boost button?
KTM R&D, Kiska Design and all our factory riders had their say in shaping the plastics. Their goal: complete harmony between rider and bike. And so it turned out. Perfect ergonomics and contact points, maximum freedom of movement, a low seat height and sweet comfort, especially in the rear part of the seat. The I-beam structures of the front and rear fenders are prime examples of such an intelligent design, guaranteeing maximum stability and a low weight thanks to well thought-out construction and mounting. Plus: they stay cleaner for longer.