KTM pulls out all the stops with completely redesigned two-stroke and four-stroke Enduro models. A new model, the 150 XC-W, also joins the family.
KTM released information on its 2017 Enduro and XC (cross-country) lineup, making the announcement last night during a press launch in Les Comes, Spain.
KTM says that the Enduro models have been completely revamped, with new all-new chassis, all-new engines. In addition to new engines and chassis, the Enduro machines also feature new suspension that includes a new WP XPlor 48 upside-down split fork (some XC models receive the WP AER 48 air fork). In fact, at least 90 percent of the components on all the 2017s are new, and the company reports that it has shaved as much as 11 pounds off every model.
The 2017 KTM Enduro lineup also includes a new two-stroke model, the 150 XC-W, replacing the 200 EXC. The XC-W is designed for closed course racing. The 250 EXC and 300 EXC complete the two-stroke family, while the four-stroke includes completely updated versions of the 250 EXC-F and 350 EXC-F models, as well as modifying the name of the higher capacity models, which are now known as the 450 XC-F and 500 EXC-F.
The special-edition Six Days models also return for 2017. Available in two-stroke and four-stroke variants, they feature what KTM calls “several performance-enhancing and useful technical parts” as well as special graphics.
Of the new models, KTM Off-Road Product Manager Joachim Sauer said, “As the saying goes, after the race is before the race. According to our understanding in state-of-the-art development, the brand new line-up of our off-road competition Enduros are proof of KTM`s ongoing commitment to our core discipline. We believe this Enduro sportmotorcycle range will push the excitement and satisfaction of any rider to a new level.”
2017 KTM 500 EXC-F
Engine
The largest-displacement model in the 2017 KTM Enduro range, the 500 EXC-F has been redesigned with the intention of making it the smallest and lightest 500 ever. The redesign starts at the top of its 510.4cc, liquid-cooled, fuel-injected, four-valve Single, which features a new SOHC cylinder and camshaft along with a redesigned water jacket. The rocker arms are designed to be more rigid, and the timing chain has been shortened and now rides against chain guides designed to reduce parasitic drag inside the engine. The cylinder head is attached to the chassis via two new lateral brackets designed to help quell engine vibration.
A shortened cylinder houses a 95mm, forged box-in-box type piston with an ultra-light piston pin. KTM engineers revised the piston crown shape to match the combustion chamber in the new cylinder head. The 500 EXC-F’s 72mm-stroke crankshaft has been redesigned for increased rigidity, and it employs a shorter connecting rod, which helps to keep things more compact. KTM says that the engine didn’t lose any weight compared to last year’s model, but it does deliver 5% more inertia, and a higher balancing factor helps it to run smoother than the previous engine.
A plain big-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 pressure lubrication. KTM says that the design enhances the engine’s durability, allowing long crankshaft service intervals. Sealing the crank with metal shims instead of seal rings reduces the sapce needed in the crankcase to give the engine a slimmer profile. A shorter primary ratio (31/76 instead of 32/76) reduces the shaft distances inside the engine, also in the name of making the engine more compact. Another space and complexity reducing trick can be found in the 500 EXC-F’s multifunctional, side-mounted counter balance shaft design, which also drives the water pump.
Of course, with all of the space-saving efforts going on inside the new KTM motor, new cases needed to be employed. The die-cast cases allo for greater centralized mass by raising the crankshaft 7mm and positioning it 9mm farther back in the lower end to improve the 500 EXC-F’s center of gravity. The new cases are also 550 grams lighter than the old ones. They also incoroporate redesigned engine covers with a new surface structure designed to reduce the wear caused by the rider’s boots.
To cool the big 510.4cc motor, KTM has employed its tried-and-true cooling system that routes the coolant from the cylinder head through the frame triangle, directly to the 500 XC-F’s WP-manufactured aluminum radiators. The new radiators feature a new filler cap system and are made of a stiffer alloy than previous versions. The 500 EXC-F is also fitted with an ECU-regulated radiator fan as standard equipment. New radiator guards have also been integrated in the front part of the spoilers to provide better crash protection..
The 500 EXC-F’s Keihin Engine Management System guides the electronic fuel injection, which features an all-new 42mm Keihin throttle body. KTM says that the injector position inside the throttle body enhances throttle response gives, and the EFI utilizes separate systems for cold starts and idle adjustment await you. The ECU also features a map switch that allows the rider to tailor the 500 EXC-F’s power curve. Like the Husqvarna off-road model, the KTM also features traction control system to aid traction by preventing wheel spin in slick or slimy conditons.
The 500 EXC-F also receives a new six-speed gearbox featuring a low-friction coating on the shift forks, special surface treatment on the fifth and sixth gears and a reworked shift drum. All KTM four-stroke engines are fitted with a gear sensor that syncs the power curve to the gear you’re in and the surface you’re on. A “No Dirt”´ gear lever design prevents dirt from blocking the joint of the lever to help achieve smoother and more precise shifting.
The 500 EXC-F’s DDS (Damped Diaphragm Steel) clutch design employs a diaphragm spring instead of the usual coil springs, which KTM says makes for a easier clutch action. The clutch also features a damping system integrated into the clutch hub for better traction and shock protection to the engine when rocks and roots are encountered. The clutch basket is claimed to be wear-free, and it is lighter than before, with a reworked inner hub and a pressure plate also providing better oil supply and unsurpassed cooling. Actuation is via a Brembo hydraulic unit.
The 500 EXC-F is fitted with a unique electric starter powered by a Lithium-ion battery. KTM is so confident in the reliability of the system that it did not incorporate a kick-starter for back-up. However, for doubters a retrofit kicks-starter kit is available through KTM’s PowerParts accessory division.
Chassis
KTM engineers put the new Enduro chassis on a serious diet, and the 500 EXC-F’s lightweight chrome-moly steel frame has redesigned to provide less weight while retaining high torsional rigidity and low longitudinal stiffness, which equates to more comfort and less rider fatigue. KTM claims that the new main frame is 2.2 pounds lighter than that of the lightest competitor on the market, and its aluminum subframe weighs less than 900 grams.
This redesigned chassis also incorporates a different mounting position of the PDS (Progressive Damping System) shock, to provide more supple rear suspension action. The 500 EXC-F’s cast aluminum swingarms weighs 220 grams less than the previous swingarm while retaining the proper flex that KTM engineers sought. The swingarm’s single-component casting process also eliminates any inconsistencies and inherent weak points created by welding.
The 500 EXC-F’s “No Dirt” footpeg design helps prevent mud and dirt build-up on the pegs. The EXC model pegs are also mounted 6mm higher than the ones used on KTM’s SX motocross models versions, which benefits ground clearance.
Suspension
Big news surrounding the 2017 KTM Enduro models involves an all-new WP XPlor 48 (mm) upside-down fork, which delivers 11.8 inches of travel. A split fork design, XPlor is fitted with a spring on both sides but features separated functions for each fork leg, with compression damping adjustment on the left side and rebound damping adjustment on the right side. Dials on top of the fork tubes (30 clicks each) offer a wide range of adjustability. In addition, a longer and sealed hydro-stop is claimed to provide better bottoming resistance. A new, optional preload adjuster allows for a threefold spring preload setting without any tools. KTM says that the XPlor is about 200 grams lighter than its predecessor.
Out back, a WP XPlor PDS shock is directly connected to the upper side of the swingarm, and KTM says it has been revised to provide the proper suspension geometry with the new frame and swingarm architecture. For this reason, the shock is now mounted 5mm closer to the frame centerline, which means nearly symmetrical loads for the swingarm and frame and more space for the exhaust.
The XPlor shock features an all-new body with a smaller piston (reduced from 50mm to 46mm) and a larger reservoir. The shock length 2.5mm shorter, and the shock stroke is 4mm shorter. A second piston works together with a closed cup (instead of a needle) toward the end of the stroke and is supported by a progressive shock spring. KTM reduced the shock’s weight by more than 600 grams.
Other New Stuff
The 500 EXC-F’s NEKEN aluminum handlebars feature a newly developed throttle assembly with an aluminum body and straightforward free-play adjustment. Interchangeable throttle cams can be retrofitted for different throttle response characteristics based on rider preference.
The new chassis features a revised airbox design, incorporating new snorkels to guard against against muck ingestion while ensuring maximum airflow. The large Twin Air filter is mounted in a stiff cage, which at the same time holds the system in place. The design allows for air filter changes in mere second without requiring tools.
A new lightweight polyethylene tank boasts a capacity of 2.25 gallons, and KTM says that its see-through plastic material always makes it easy to see how much fuel is left at a glance. All frou-stroke models are fitted with an integrated fuel pump system and an additional fuel level sensor. On the new models the fuel line features a 90° connector to the tank for better protection against damage.
KTM says it put a lot of effort into the development of the new four-stroke Enduro exhaust systems. All four-strokes receive new header pipes and a shorter silencer, mounted as close to the engine as possible for better mass centralization. Changed to the muffler internals are also intended to keep noise below the FIM noise limit.
A new seat is designed for better comfort while being 10mm lower than before to help you master the most challenging terrain. KTM R&D also worked with Kiska Design and KTM’s factory riders to reshape the 2017 bodywork so that it had better ergonomics and fewer contact points for maximum freedom of movement. The I-beam structures of the front and rear fenders are new as well, designed for maximum stability and reduced weight. KTM says the fenders will also stay cleaner for longer.
KTM’s wheels feature lightweight, CNC-machined hubs and Giant rims shod with the latest Maxxis tires. The rear tire features a reworked profile and internal structure for better grip under wet conditions, and it is claimed to be more resilient to punctures.
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