WIDE OPEN TRACK ATTACK
With the agility of a 125 and a healthy dose of extra power, the KTM 150 SX is a lively package ready to take on the 250 cc 4-strokes. From within its completely reworked new chassis, the compact, lightweight engine produces class-leading torque and power. Everything about this motorcycle screams high-performance fun and it goes into battle as the ultimate on-track competitor.
ENGINE & EXHAUST
The pure exhilaration that this bike's engine delivers warranted further development and continued production. As it shares many of its key components with the class-leading 125, the cylinder, cylinder head and piston unit can now also be fitted on a 125cc engine base, converting it to a 150 SX without having to replace the crankshaft. Compact and powerful, this innovative 2-stroke engine is a lightweight powerhouse that makes perfect sense.
At the core of the 150cc engine is a reworked cylinder. It has a 58 mm bore and features an improved power valve unit with a sophisticated mechanism for the lateral support exhaust ports. The new exhaust port layout increases engine performance, while the upper contour of the exhaust port has been machined to ensure more accurate port timing. Together with the two-component cylinder head, the cylinder is key to the KTM 125 SX's outstanding performance across the entire rev range.
CRANKCASES AND ENGINE COVERS
The lightweight and compact engine cases are manufactured using a high pressure die-cast production process that reduces weight, whilst retaining strength and durability. The design allows for a higher crankshaft position which is located closer to the center of gravity, resulting in optimal mass centralization and easier ride-ability. Additionally, for 2019 the seat of kickstart intermediate gear has been reinforced for improved reliability and thanks to the new clutch arrangement, the clutch cover is lower, reducing the engine width by 10 mm.
The KTM 150 SX is now fitted with a new, more robust 6-speed transmission. The gear ratios were carried over from the predecessor, but all the gears feature improvements and reinforcements. Another highlight of the 150 SX transmission is the no dirt gear shifter. Similar to the foot peg design, it prevents the build-up of dirt and ensures the next gear is always available, no matter what the conditions.
The KTM 150 SX is fitted with a MIKUNI TMX carburetor. This 38mm flat slide carb lives to provide smooth and controllable power all the way up to the rev limitation. With a new intake manifold the carburetor is turned 7° in order to reduce the overflow of fuel. And it's less sensitive to different altitudes and temperatures, so you can pin it wherever, whenever.
All 2-stroke models feature a new CDI control unit with an advanced hardware which improves the starting behavior of the engine. The ignition curves remain unchanged.
At the heart of the engine, the crankshaft features a 72 mm stroke that produces the optimal torque and revs. It has been ideally balanced and with the counter balancer shaft, resulting in minimum vibration. The crankshaft is placed in the perfect position to centralize mass, contributing to better agility and handling.
Maintaining the optimal engine temperature is crucial to ensuring consistent horsepower throughout the ride. The KTM 150 SX features newly designed radiators which are mounted 12 mm lower than the predecessors. This lowers the center of gravity and matches the design of the new shrouds perfectly, in order to achieve perfect ergonomics. By using CFD technology (computational fluid dynamics) together with a clever coolant circuit routing, the innovative system ensures the optimum engine temperature for the highest performance, no matter what the conditions. The radiators also feature special protectors that don't only serve as protection from flying rocks and debris but also as a brace that disperses energy around the radiators in the event of an impact.
When it comes to improved power delivery and performance, the new exhaust plays a key role and packs a punch that is hard to beat. In addition, its new shape provides slimmer ergonomics while still operating safely within the noise limits for racing.
The KTM 150 SX is just made to be ridden aggressively, resulting in the development of a new chassis that is light and responsive enough to further enhance its dynamic reputation. For 2019, the KTM 150 SX features a new lightweight, high-tech steel frame that not only responds well to aggressive inputs, but has also been optimized to provide exceptional feedback to the rider. The new flex characteristics soak up those unwanted hits while also delivering excellent agility and high-speed stability. As a whole, this new chassis gives the rider the confidence to be 100% in charge of the ride.
The all-new KTM 150 SX frame is professionally crafted from hydro formed Chromium Molybdenum steel tubes that are robot welded, ensuring the highest levels of consistent quality. With improved stiffness for more responsive handling, while working in total harmony with the suspension, for uncompromised high-speed stability. The frame also features "no-dirt" footpegs which have a simple but effective self-cleaning system that ensures the footpegs return to their original position, providing complete control in all conditions. For 2019, all SX frames feature the same highly durable powder coating as the KTM Factory machines and come with standard frame protectors. A new 40 mm longer lightweight aluminum subframe ensures better rear fender stability.
The KTM 150 SX features an improved one-piece swingarm, with 5 mm of extra axle adjustment thanks to a reshaped axle slot. This allows the wheel to be set further back, for increased stability on the roughest tracks. Manufactured using a gravity die-cast production process, it offers exceptional strength at the lowest possible weight. The chain measurement markings on the swingarm are visible from above, making chain adjustment simpler and more accurate.
KTM uses lightweight, CNC-machined hubs and high-end Excel rims on all SX models, guaranteeing maximum stability and minimum weight. For 2019, the aluminum spoke nipples feature a reworked design, which conveniently reduces the frequency with which the spokes need to be tightened. The wheels are fitted with the latest Dunlop Geomax MX 3S tires, delivering maximum grip and stability and effectively transferring all the power to the ground.
All full-size SX models are fitted with the super-lightweight WP AER 48 front fork. It is a 48 mm USD air-sprung fork with separate functions for each fork leg, meaning damping functions are on the right side and the air spring is on the left. The left leg features a two-chamber system with a capsuled air cartridge, helping prevent loss of air pressure. Essentially, this means that in the rare case of a leaking outer seal, the internal cartridge pressure keeps the bike in a normal position. The air spring is exceptionally easy to use and can be adjusted to any rider weight via a single air valve and the air pump that is supplied with the bike. The right fork leg integrates a damping cartridge to fit single damping leg requirements and can be adjusted to the track conditions and the rider's preferences. (compression from top, rebound from bottom, 30 clicks each). For 2019, new settings on the damping side have improved the damping characteristics, providing great front end feel and control.
All SX models feature a DDC monoshock, which has been developed to work as a complete unit with the entire frame and swingarm architecture, as well as the linkage system and the AER 48 forks. It features high-quality machined and anodized components, which add a touch of class and give it appeal beyond just a functional necessity. Internally, the shock houses an updated main piston and new settings that provide improved damping characteristics, perfectly complimenting to the reworked front-end setup. It is fully adjustable, including high and low speed compression, allowing you to set the shock up precisely to suit any track and rider's preferences.
All SX models feature top quality, CNC-machined triple clamps and have become somewhat of a KTM trademark. For 2019, the triple clamp has been reworked with stiffer upper clamps (22 mm offset for all models) to suit the reworked frame stiffness and flex characteristics of the latest WP AER forks. The result is a front end that works in perfect harmony with the frame, improving overall handling and stability. The rubber damped handlebar fixation reduces vibration and also allows for some adjustment with 2 different mounting positions. An hour meter is fitted as standard on the upper triple clamp on all SX models, keeping the rider informed of the number of hours spent tearing up the track and when the next service is due.
High-tech Brembo brakes have always been standard equipment on all KTM motocross bikes. Combined with lightweight wave discs, the renowned system provides the highest level of braking efficiency, enabling you to out-brake the competition.
All models in the SX range are fitted with newly designed lightweight polyethylene fuel tanks. The fuel capacity on the full-size SX models is still 7 liters, but the new shape improves the ergonomics. The filler cap has an inside thread that makes for easy and reliable closure.
The new airbox on the KTM 150 SX has been completely reworked to ensure better flow dynamics, resulting in optimal power and throttle response. Despite the obvious performance enhancements, the new design also offers maximum protection against soiling of the air filter. The large Twin-Air air filter is mounted on a cleverly designed stiff cage that minimizes incorrect installation. As found on previous models, filter maintenance is quick and easy and does not require tools - a standard, original feature from KTM.
ERGONOMICS & COMFORT
When it comes to attacking the track, chasing faster times with every lap, there is no better weapon than the KTM 150 SX. Its performance-inspired design allows the rider to shift his weight quickly and easily, working in perfect harmony with the motorcycle. KTM has focused extensively on creating bodywork and ergonomics that are shaped for high-level performance, ensuring a riding position that offers the best riding position for control. A rider's main interaction with the bike is through the bodywork, footpegs, handlebars. No compromises were made in these important areas and only the best quality products and designs can be seen on all SX models. KTM produces dynamically fast motorcycles and every effort goes into making sure the rider has the ability to confidently control it.
All SX models have a newly shaped seat, designed to match the improved ergonomics. The seat cover features newly developed silicone strips that provide better feel and grip for the rider. The seat is conveniently fixed to the bike using one long, lateral screw, making it safe and easy to handle.
All full-size SX models are equipped with the same high-strength aluminum tapered handlebar, made by NEKEN. The handlebar is fixed in rubber damped mountings, which allow for two different positions. The handlebars come standard with an ODI vulcanized grip on the right side and a comfortable ODI lock-on grip, which does not require any wire or glue, on the left. They also feature a reworked bar-pad with a newly designed cover that can be attached and removed a lot quicker and easier. These handlebars offer the control a 150cc rider is looking for, allowing him to ride it like a 125 and still hang on to the little extra power.
Sophisticated Â´No DirtÂ´ footpegs prevent smudging up the pegs, even when digging in deep ruts. Looking for a higher riding position? Then just mount the footpegs of the MY2018 EXC models, which are 6mm higher than the SX versions.
BODYWORK & GRAPHICS
Those who ride a KTM 150 SX thrive on the extra power it delivers, while still having the dynamic agility and feel that a 125 cc offers. These riders are always pushing themselves and their machines to the limit and need the freedom of movement to position the bike where they want it on the track. With input from KTM factory riders, KTM R&D as well as Kiska Design, the bodywork on the entire SX range achieves perfect harmony between rider and bike, providing the manoeuvrability the rider expects and the control he needs. The bodywork also contains intelligent design elements, like the I-beam structure on the front and rear fenders, which guarantee maximum stability without adding any extra weight. The new graphics suit the aggressive nature of the bike and further enhance the high performance style of the bodywork.
The 2019 SX models feature the latest in-mold graphics, matching the new bodywork perfectly. They have a fast and aggressive style that screams READY TO RACE, leaving no doubt as to the bikes' high-performance intentions.
SOFTWARE & ELECTRONICS
Absolute performance purity is the name of the game when it comes to electronics and the new KTM 150 SX. Undiluted 2-stroke simplicity, with an hour meter to keep a check on how long you've been shredding and an optional rev counter to assist with perfect setup.
1-cylinder, 2-stroke engine
Wet multi-disc clutch, hydraulically actuated
25CrMo4 steel central-tube frame
WP-USD, AER 48, Ø 48 mm
WP shock absorber with linkage
Suspension travel (front)
Suspension travel (rear)
Front brake disc diameter
Rear brake disc diameter
5/8 x 1/4"
Steering head angle
Tank capacity (approx.)
Weight READY TO RACE (without fuel)
The illustrated vehicles may vary in selected details from the production models and some illustrations feature optional equipment available at additional cost.
All information concerning the scope of supply, appearance, services, dimensions and weights is non-binding and specified with the proviso that mistakes, printing, setting and typing errors may occur; such information is subject to change without notice.