The 2027 KTM 300 SX in ORANGE is built for motocross riders who want big-bore 2-stroke performance in a focused, race-ready package. At its core is a 293.2 cm³ 1-cylinder, 2-stroke engine with Keihin EFI (39 mm throttle body) managed by Vitesco Technologies EMS, paired with a 5-speed transmission and an electric start system. Chassis updates developed with input from KTM Factory Racing target improved flex and feel, while WP XACT suspension at both ends supports fast, track-tunable control. From selectable engine maps to Brembo hydraulics, it’s a purpose-built machine for chasing laps and gates.
The 300 SX pairs a 293.2 cm³ single-cylinder 2-stroke engine with Keihin EFI fuel-mixture generation (39 mm throttle body) and a power valve for more usable power across the rev range. Vitesco Technologies EMS supports consistent fueling, and a handlebar map select switch lets you choose between two engine maps—one more linear and predictable, the other crisper and more aggressive.
KTM’s revised frame updates were developed with input from KTM Factory Racing, with changes focused around the rear shock mount area and updated engine mounts and cut-outs aimed at improved chassis flex. The central double-cradle-type 25CrMo4 steel frame works with an aluminum-reinforced polyamide subframe, while details like CNC-milled triple clamps and a forged steering head connection are designed for precise fork alignment and stability.
Suspension is WP XACT at both ends, with a 48 mm WP XACT-USD (AER) fork up front and a WP XACT monoshock with linkage at the rear. KTM also emphasizes quick, easy setup: tool-free adjustability is designed in, including hand-adjustable rear high- and low-speed compression and accessible fork clickers for compression and rebound, helping you tailor feel for changing track conditions.
The 2027 KTM 300 SX uses a 293.2 cm³ 1-cylinder, 2-stroke design with Keihin EFI and a power valve to deliver smoother, more controllable drive through the rev range. EFI reduces the need for traditional jetting changes, and the bike’s Vitesco Technologies EMS supports consistent management of the system. When conditions or preference change, the map select switch provides two engine map choices: Map 1 is described as linear and predictable, while Map 2 is a crisper, more explosive delivery.
Power is sent through a 5-speed transmission, and the bike features a wet, DDS multi-disc clutch with Brembo hydraulics for clutch operation. Primary drive is listed as 26:72, with clutch primary drive teeth at 72.
Up front, the WP XACT-USD (AER) Ø 48 mm fork uses an air-spring concept with a pressurized oil chamber, with design elements intended to keep damping progressive and consistent while reducing pressure peaks. KTM notes settings designed to complement the frame and rear linkage, and adjustment is straightforward via a single air pressure pre-load valve along with click adjusters for compression and rebound. Suspension travel is 310 mm (12.2 inch) at the front.
At the rear, the WP XACT monoshock with linkage is supported by compression and rebound adjustment, with KTM highlighting hand-adjustable dual compression (high- and low-speed) for quick changes. Rear suspension travel is 300 mm (11.81 inch), and the geometry is described as increasing ground clearance at the linkage to reduce the risk of bottoming out.
The KTM 300 SX is built around a central double-cradle-type 25CrMo4 steel frame with an aluminum-reinforced polyamide rear subframe design. KTM’s 2027 frame revisions focus on areas around the rear shock mount and updated engine mounts, aiming to refine chassis flex characteristics. Ground clearance is listed as 354 mm (13.94 inch), and seat height is 958 mm.
Braking is handled by disc brakes front and rear. KTM also calls out practical durability and service-focused touches, including modified wiring harness fixing points and routing intended to be less prone to wear and damage, along with a durable chain guide and chain guard designed to reduce the chance of hooking external objects and to minimize dirt build-up. The bike uses a 520, non-sealed chain.
The 2027 KTM 300 SX lists a weight (without fuel) of 99.4 kg. Fuel capacity is shown as 7.2 l (1.9 US gal). These numbers, combined with the bike’s motocross-focused ergonomics and chassis layout, help define it as a purpose-built race platform rather than a cross-over machine.
Ergonomics are supported by bi-compound tank shrouds intended to channel air toward the radiators, along with a tighter fuel tank roll and a rider triangle developed to improve knee contact and gripping surfaces—especially when standing on the pegs. It’s a cohesive layout designed around active riding and frequent body movement.
As always, the suspension boasts an easy tool-free setup at both ends, ensuring you chase down the podium in total control. On the rear, a hand-adjustable dual compression option allows riders to adjust high- and low-speed settings in a matter of seconds. The forks on the front end are also easily modified thanks to hand-adjustable clickers on the bottom of the fork shoe and top cap.
Pre-mix gets a remix across the 2-stroke KTM SX range, with Electronic Fuel Injection setting the standard. Now there's no setup pre-race, And thanks to the Keihin EFI and reed valve case design, you can be guaranteed of laying down optimal power at any altitude, all of the time. For 2026 there is a new fuel protector cap: you'll still have quick and easy access for maintencance but now more safety against any outside damage and accidental opening as well as preventing dirt from entering the sides of the connector.
Picture this; You're 7 laps into an absolute ripper of a race. You miss your line and end up stalling in a deep rut. But don't sweat it. All you do is press the starter button and you blast off again to take the flag. This is the reality on the KTM SX models. Thanks to a 12,8V 2 Ah lithium ion battery is placed under the rider's seat, a high-quality starter & pickup and super robust design, the only thing you'll be kicking - is ass.
The KTM SX and SX-F range is engineered and designed to provide riders with easy-to-access service parts, as well as suspension adjustability. This permits faster trackside and off-season maintenance, as well as simplifying motocross for novice riders without pit crews. For 2026, a new threaded radiator cap allows easier and faster opening with reduced force.
With EFI comes great rideability. Along with the electronic fuel injection and a power valve on the KTM SX models, allowing for more usable power throughout the rev range. Smoother power means better traction. Better traction means holeshot heaven!
The 300 cc 2-stroke powerhouse brings a only choice of weapon into the MX Open category and provides more choice for racers looking for maximum power at the least possible weight. Along with low maintenance costs, an overall engine mass of just %":& LB (23,9 kg), the KTM 300 SX provides pure performance. And then some.
The KTM SX models features a map select switch allowing the racer to switch between 2 engine maps. Map 1 provides a linear, predictable power delivery, while Map 2 gives it the full beans with crisp, explosive power output.
Get ready for a full-on berm assault. The KTM SX and SX-F machines feature revised frame updates developed with input from KTM Factory Racing. For starters, the area around the rear shock mount is streamlined, with optimized engine mounts and cut-outs for improved chassis flex. The front area of the frame features optimized wall thickness with updated engine mounts.
Tank shrouds using bi-compound plastics channel air towards the radiators more efficiently, while a concise fuel tank roll, makes for a tighter, more secure fitment, reducing the chance of frame scrubbing and dramatically improving durability. All this works alongside the specially-developed rider triangle, to provide unmatched knee contact and gripping surfaces - especially when standing on the pegs.
Let's get the technical parts out of the way first; the 48 mm WP XACT AER forks fitted to the KTM SX and SX-F line-up features a capsulated air spring and pressurized oil chamber for progressive and consistent damping, while oil and air bypasses reduce pressure peaks. In combination with the mid-valve damping system, all this provides exceptional feedback and rider comfort. The fork also has settings which not only compliment the frame and rear linkage, but ensures stellar performance at all levels. Speaking of settings, these are easily adjusted via a single air pressure pre-load valve, as well as easy-access click adjusters for compression and rebound. Additionally, the WP air pump needed to adjust the fork's air pressure is provided as standard in the buy-pack.
Keeping things in check at the rear, the WP XACT rear shock uses settings directly from the KTM Factory Racing Teams. The frame and shock geometry provide increased ground clearance at the linkage, reducing the risk of bottoming out. Small-diameter linkage bolts save weight, while refined linkage seals improve rear shock response and advanced damping characteristics. Proper setup is advised for optimal performance.
The KTM Motocross range has a special rear brake pedal adding additional stiffness, bending resistance and braking feel to the overall package. At the other end, a forged steering head connection and CNC-milled triple clamps, make for the perfect alignment of the fork tubes. This precise geometry of the fork clamps ensures highly responsive and smooth fork action - not to mention unwavering stability when charging across ruts and onto the podium.
Getting power hooked into the dirt is a tough job. However, hours of research and testing have led the KTM Motocross range to the Dunlop GEOMAX MX34. Providing unmatched stability and control at the highest level, the rubber features a rigid carcass and rubber compound that improves damping and absorption, maintaining performance up to 30% longer than previous models. Progressive Cornering Block Technology also improves grip in the berms, while the rear pattern has a tall and wide center block for desirable traction and control everywhere else. Lastly, this unique block arrangement works to dispel mud buildup, ensuring traction in even the muddiest of track conditions.
Pre-mix gets a remix across the 2-stroke KTM SX range, with Electronic Fuel Injection setting the standard. Now there's no more fiddly jetting setup pre-race, And thanks to the Keihin EFI and reed valve case design, you can be guaranteed of laying down optimal power at any altitude, all of the time. The fuel protector cap delivers easy maintenance access combined with improved protection against impact, accidental opening, and dirt ingress at the connector sides.
The shock absorber geometry on the KTM SX and SX-F machines gives decent ground clearance for the linkage, with the topology-optimized die-cast footpegs being less susceptible to hooking on deep ruts, and take-offs when scrubbing.
Count on a durable chain guide and chain guard and minimize the chances of hooking on external objects - especially in extremely muddy terrain while reducing dirt build-up around the swingarm and rear sprocket. For 2027 we've also modified the fixing points and routing of the wiring harness so it's less prone to wear and damage.
With a strong focus on mass centralization, KTM SX and KTM SX-F engines are designed to concentrate rotating mass at the core, working in perfect harmony with the chassis. The result is lighter, more agile handling that runs rings around the competition.
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