2026  KTM  125 SX  - 42517M

2026 KTM 125 SX

FULL-SCREAM AHEAD

There are very few sounds that can't be beaten: the crack of a soda can on a blistering hot day, the ping of the perfectly executed golf shot, and the scream of a 125 cc 2-stroke full throttle. The KTM 125 SX takes its leads directly from the KTM Factory Racing team for pure performance, pure results. Like the sound it makes, you won't forget it.

01. Before The Gate

CHUGGA CHUGGA, RING DING DING! ELECTRIC START
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 you don't sweat it. All you do is press the starter button and you blast off again to take the final flag. This is the reality on the 2025 KTM 300 SX. Thanks to a 12.8V 2 Ah lithium ion battery is placed under the rider's seat, a high-quality stator & pickup and super robust design, the only thing you'll be kicking - is ass.

LESS FOCUS ON THE TOOL, MORE FOCUS ON THE TRACK SERVICEABILITY
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.

02. Start Strong

UNMATCHED PERFORMANCE
PERFORMANCE
Designed to churn out torque, the KTM 125 SX is set to continue its dominance in its class with unrelenting forward momentum. The overall engine weight is only 39.7 lb (17.86 kg) and carries impressive horsepower figures. This lightweight powerplant retains its typical high-revving character while laying down the grunt where it matters most.

PICK YOUR POWER
SELECTABLE MAPS
Once again slicing into the 125 cc class with the leading edge of technology, the KTM 125 SX features a map select switch allowing the racer to switch between 2 engine maps. The White Map - or Map 1 - provides a linear, predictable power delivery ideally suited to attack hard-packed dirt with a leaner air-fuel mixture. Alternatively, the Green Map - Mapping 2 - is tuned for loose, thick sandy conditions with a richer mix.

03. Calm Under Fire

FLUID RIDER MOTION
ERGONOMICS
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.

SLEEKER FOR YOU TO SCRUB CLEANER ABSOLUTE CONTROL
Get ready for a full-on berm assault. The KTM SX and SX-F machines received major frame updates directly from KTM Factory Racing efforts. For starters, the area around the rear shock mount is streamlined, with engine mounts and cut-outs for improved chassis flex. The front area of the frame has an optimum wall thickness with renewed engine mounts.

04. Hit The Big Stuff

RACING ON RAILS STABILITY
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.

TIRES
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.

05. Maintaining Momentum

NOTHING TO HOLD YOU BACK
GROUND CLEARANCE
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.

PRECISE, LAP AFTER LAP
CONSISTENCY
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 2026 we've also modified the fixing points and routing of the wiring harness so it's less prone to wear and damage.