Motorcycle specifications KTM150 SX 2019 Crossing a half-landing

The character of the 2-stroke is irreplaceable, its power praised. For those who want to preserve dynamics while gaining watts, KTM has placed this machine at just the right intermediate level. As nimble as a 125, the KTM 150 SX is powerful enough to challenge 250cc 4-strokes. Supported by a completely reworked chassis, the compact, lightweight engine delivers torque and power unexpected on this type of displacement. Its level of performance and playful spirit are sure to delight born competitors.

engine

the exhilaration of this motorcycle's engine is the result of long development and continuous production work. This bike incorporates most of the key components of the class-leading 125. Now, the cylinder, cylinder head and piston can also be mounted on a 125 cm³ engine base to convert it into a 150 SX without replacing the crankshaft. A real powerhouse, this innovative 2-stroke engine now comes into its own.

cylinder

the cylinder, with a 58 mm bore, has undergone several improvements in the 150 cm³ engine. With a 58 mm bore, it features an optimized control spindle and a sophisticated mechanism for the exhaust channels in the side support. The new configuration of the exhaust channels contributes to increasing the engine's performance level. The upper contour of these components has even been machined to ensure ultra-precise timing. Combined with the two-piece cylinder head, this cylinder is responsible for a clear increase in power across the entire rev range of the KTM 125 SX.

crankcases and covers

the use of a high-pressure die-casting process results in a relatively compact and lightweight crankcase, while preserving its strength and durability. The crankcase design has enabled KTM engineers to raise the position of the crankshaft closer to the center of gravity, to better centralize mass and enhance rideability. On 2019 models, the intermediate starter pinion seat has also been strengthened to improve reliability. Thanks to the new clutch arrangement, the clutch housing is now positioned lower, saving 10 mm on the width of the engine block.

gearbox

the KTM 150 SX is now equipped with a new, more robust 6-speed gearbox. The transmission ratios of the previous version have been retained, but the sprockets have all been improved and reinforced. Another highlight of the transmission on the KTM 150 SX is the "zero dirt" design of the selector. Designed on the same principle as the footrest, it prevents the accumulation of dust and enables the gearbox to remain operational in all conditions.

carburetor

the KTM 150 SX is equipped with a MIKUNI TMX carburetor. This 38-mm flat-barrel carburetor offers a clear improvement in power delivery right up to the rev limiter. Thanks to a new distributor tube, the carburetor has been rotated by 7° to reduce the risk of fuel overflow. It is also less sensitive to changes in altitude and temperature.

contact

all 2-stroke models feature a new capacitor-discharge ignition control unit capacitor discharge ignition control unit and advanced components designed to improve engine starting behaviour. Ignition curves remain unchanged.

crankshaft

the 72 mm-stroke crankshaft guarantees superior torque and maximum power. Perfectly balanced, it is combined with a balancer shaft to minimize vibration. Ideally positioned for optimum mass centralization, it contributes to the bike's agility and roadholding.

cooling

to ensure smooth power delivery, it's essential to maintain optimum engine temperature. To this end, the KTM 150 SX is equipped with new radiators that are 12 mm lower than those of its predecessor. This position, perfectly matched to the design of the new spoilers, lowers the center of gravity and enhances ergonomics. Thanks to numerical fluid dynamics (CFD) simulation calculations and a clever cooling circuit, this innovative system ensures that engine components are kept at the ideal temperature to guarantee the highest level of performance, whatever the conditions. Special radiator guards not only protect the radiators from stones and other debris, but also distribute the force of impact around them.

muffler

the new exhaust system gives the engine a smoothness and liveliness that are hard to match. Its shape is also a real plus in terms of ergonomics, while respecting the noise emission levels recommended for racing.

chassis

the KTM 150 SX has been designed for an aggressive riding style. That's why KTM has developed a new chassis that's lighter, more responsive and more dynamic than ever. The 2019 version of the KTM 150 SX relies on a new high-tech steel frame capable not only of reacting precisely to the rider's repeated assaults, but also of offering excellent feedback. The frame's flexibility has been specially designed to absorb unexpected ground movements and enhance the bike's agility and stability at high speeds. All in all, this new chassis allows the rider to remain totally in control of his riding, and with complete confidence.

frame

the KTM 150 SX's state-of-the-art chromium-molybdenum steel frame consists of hydroformed tubes assembled by automated welding, to guarantee the highest level of quality. Rigidity has been optimized to enhance handling. The excellent cohesion with the suspension offers the perfect compromise between agility and high-speed stability. With self-cleaning "zero-dirt" footrests that won't jam when returned to position, you're in complete control, whatever the conditions. The frame of all 2019 SX models inherits the highly resistant powder coating (used on KTM Factory machines) and standard frame protectors. The new 40 mm longer rear buckle is made of lightweight aluminum to improve rear shell stability.

swingarm

the KTM 150 SX benefits from an optimized monoblock swingarm offering 5 mm extra play thanks to the special shape of the axle housing. This allows the wheel to be set back to improve stability on the most demanding tracks. The high-pressure die-cast swingarm has been designed for maximum strength, while keeping weight to an absolute minimum. The chain measurement markings on the swingarm are clearly visible from above, making adjustment much easier.

brakes

state-of-the-art Brembo brakes are standard equipment on KTM motocross bikes. Combined with Wave brake discs renowned for their lightness, they deliver the stopping power expected by the most daring riders.

fuel tank

all SX models feature a new, ultra-light polyethylene fuel tank. Capacity on standard-size SX models is still 7 liters, but the shape of the tank is more ergonomic. The internally threaded fuel filler cap ensures easy, reliable closure.

air filter housing

the air filter housing of the KTM 150 SX has been completely redesigned to optimize flow dynamics and ensure exceptional power delivery and acceleration. In addition to the obvious gain in performance, the new design also serves to better protect the air filter from clogging. The rigid support for the large Twin-Air filter has been designed to minimize installation errors. As on previous models, the filter can be serviced in record time and without tools, a typically KTM feature.

saddle

the saddle on all SX models has been redesigned to confirm the improvements in ergonomics. The saddle cover now incorporates silicone strips to optimize grip and feel. A long screw on the side secures the saddle to the motorcycle, making handling easier and safer.

handlebars

all standard-size SX models feature the same tapered, ultra-strong aluminum handlebars made by NEKEN. Two positions are possible for the handlebar trigger guard with shock absorbers. right: an ODI vulcanized grip available as standard; left: an ODI lock-on grip that's as comfortable as it is practical, thanks to its glue- and wire-free mounting system. The handlebar foam has also been redesigned, as has the handguard, which is now much easier to fit and remove. These handlebars offer the rider a level of control comparable to that of a 125 cm³ bike, but with added power.

software and electronics

the new KTM 150 SX boasts electronics to match its ambitions. The hour meter (available as standard) counts the hours spent in the saddle, while the tachometer (available as an option) helps you find the ideal rpm.

Information and images credits: KTM