2018 KTM 350 SX-F
Since Tony Cairoli first took a KTM 350 SX-F to the top of the MX1 World Championship in 2010, the Red Bull KTM athlete has dominated the class aboard this nimble but powerful bike with 5 (five!) consecutive world championship titles. No surprises here, with the combination of 450-style muscle and the agility of a 250. Who said you can’t have everything?
The engine of the KTM 350 SX-F features a compact and very light (27.2kg) construction. Its DOHC (double overheard camshaft) design with lightweight titanium valves and DLC coated cam followers allows for lively but strong engine characteristics. Fitted with the latest electronic fuel injection system and an E-starter, it has an extremely wide usable speed range, high performance and incredibly efficient rideability. The KTM 350 SX-F engine shares the same layout as the one in the KTM 250 SX-F, its playful handling similar to a 250 machine resulting mainly from reducing the moving masses to a minimum.
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, power peaking at 58hp. Lateral brackets made of aluminum allow an efficient fixation of the engine to the frame and contribute to the bike’s featherweight feel.
The KTM 350 SX-F is fitted with a unique E-starter as standard, which is a clear advantage when it comes to crunch time in the heat of battle. A strong starter motor made by Mitsuba will fire time and time again at the push of a button. Even under extreme conditions, thanks to its more heat resistant O-ring.
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 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 to the gear you’re in. It’s also possible to unleash an even more powerful mapping via the handlebar map select switch.
The engine is fitted with a smooth 5-speed transmission, which features a special surface treatment on the 2nd, 3rd and 4th gears for best 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. In MY18, the transmission shaft gets a new C4 bearing that has a bigger overlap in the case. This guarantees better reliability even at extremely high operating conditions. Think GP-level riding. In knee-deep sand.
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.
The KTM 350 SX-F employs the KTM-developed CSS clutch (coil spring steel) with a robust steel basket and extremely heat resistant clutch plates and new, nitrated steel liners reducing the wear. Light operation and telepathic amounts of control are standard with this hydraulic Brembo actuated clutch.
KTM engineers just love dropping weight year after year. The result: the 2018 KTM SX models are the slimmest, lightest dirt bikes out there. Even though the 4-strokes are equipped with an E-starter as a standard feature, while the competition still needs to be kickstarted. You can just focus on kicking ass.
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 headers that have a unique standard feature; an additional resonator system – a small chamber connected to the pipe. 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 noise limit, while still raising the hairs on your neck.
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.
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.
The WP shock absorber has been developed with the entire frame and swingarm architecture in mind, including the linkage 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, confidence inspiring setting with improved damping characteristics perfectly matches the front-end setup 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 2-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 fork 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). Right off the dealer floor, this fork (with reworked damping characteristics) is more comfortable and more sensitive than ever. But you can still hammer the hell out of it.
Top quality, CNC machined triple clamps have been a KTM trademark for years to ensure precise handling. The rubber damped handlebar fixation allows for two positions and an hourmeter is fitted in order to let the rider know it’s time for a service.
These high-tech Brembo babies are combined with lightweight Wave brake discs. You couldn’t brake any harder, better, faster or stronger
HANDLEBAR MAP SELECT SWITCH
All 4-stroke models are equipped with a sophisticated new multi-functional handlebar map select 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 that none of the competitors can offer. It guarantees more efficient traction when the track conditions are less than perfect. Push the tip switch and reign supreme. With this map select 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 tip switches when the engine idles and the EFI control lamp mounted on the upper triple clamps will let you know you are READY TO RACE. In addition, the map select switch gives the rider the chance to select an alternative, more powerful map beside the standard configuration. Welcome to the future.
DESIGN : 1-cylinder, 4-stroke engine
DISPLACEMENT : 349.7 cm³
BORE : 88 mm
STROKE : 57.5 mm
STARTER : Electric starter
TRANSMISSION : 5-speed
PRIMARY DRIVE : 24:73
SECONDARY GEAR RATIO : 14:50
CLUTCH : Wet, CSS multi-disc clutch, Brembo hydraulics
EMS : Keihin EMS
FRAME DESIGN : 25CrMo4 steel central-tube frame
FRONT SUSPENSION : WP-USD, AER 48, Ø 48 mm
REAR SUSPENSION : WP shock absorber with linkage
SUSPENSION TRAVEL (FRONT) : 310 mm
SUSPENSION TRAVEL (REAR) : 300 mm
FRONT BRAKE : Disc brake
REAR BRAKE : Disc brake
FRONT BRAKE DISC DIAMETER : 260 mm
REAR BRAKE DISC DIAMETER : 220 mm
CHAIN : 5/8 x 1/4"
STEERING HEAD ANGLE : 63.9 °
WHEELBASE : 1485 ± 10 mm
GROUND CLEARANCE : 370 mm
SEAT HEIGHT : 960 mm
TANK CAPACITY (APPROX.) : 7 l
WEIGHT READY TO RACE (WITHOUT FUEL): 99.8 kg