Review – Key Features – Features & Benefits – Specifications
2025 KTM 125 SX: FULL-SCREAM AHEAD.
Introducing the 2025 KTM 350 SX-F…
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 charging down a long straightaway. The 2025 KTM 125 SX takes its leads directly from the Factory Racing team and puts them to work like nothing else. Like the sound it makes, it cannot be beaten.
2025 KTM 125 SX Totalmotorcycle.com Key Features
UNMATCHED 2-STROKE PERFORMANCE
Boasting the largest arsenal of 2-stroke weaponry, the 2025 KTM SX line-up has something for everyone. From the most potent 50 cc mini-crossers to the unprecedented KTM 300 SX, the KTM SX range is primed and ready to bring the noise.
2025 KTM 125 SX BACK ON THE ATTACK
After a 2-year absence, the 2025 KTM 125 SX is bringing the 150 cc designation to a table-top near you. With a lightweight chassis, and a pure READY TO RACE attitude, the KTM 150 SX is back to set a whole new benchmark.
NEXT LEVEL MOTO
Two years ago the 2023 KTM SX line-up grabbed the holeshot with major updates across the range. For 2025, the KTM SX and SX-F brings even more firepower to the starting gate. Armed and fully loaded with chassis updates and technological advances, the 2025 KTM SX and SX-F range has total championship domination firmly in sight.
EVER-EVOLVING PERFORMANCE
The 2025 KTM Motocross lineup receives its updates directly from the KTM Factory Racing efforts. From a reworked frame to updated tank shrouds and new tires, this is our most advanced range of motocrossers yet.
- Re-worked frame with updated shock mountings and front triangle, including an improved wall thickness.
- Improved engine mounts with cut-outs to enhance chassis flex, reduce weight by 300g, maintain stability, and improve cornering.
- Updated tank shrouds with bi-compound plastics improve radiator airflow and cooling
- Updated chain glider design for improved mud dissipation.
- Upgraded suspension settings at both ends in support of the updated frame and rear linkage, improving weight distribution, stiffness, and response.
- Upgraded rear brake pedal construction for increased stiffness and resistance to bending.
- New fuel tank roll for improved fitment, reducing frame scrubbing, and enhancing durability.
- New Dunlop GEOMAX MX34 Motocross tires as standard.
- Connectivity Unit Offroad is available as KTM PowerParts for the KTM SX-F line-up with a wide range of functionalities via the KTMconnect app.
KTM TAKES RIDER CONNECTION TO THE NEXT LEVEL WITH THE 2025 KTM MOTOCROSS RANGE
In its latest update since the completely revamped 2023 KTM SX range, the 2025 KTM SX and 2025 KTM SX-F range have upped the ante when it comes to rider connection, composure, and control – along with the return of a fan favorite.
Engineered to provide riders with more control than ever before, the 2025 KTM SX and SX-F range brings a series of updates adopted directly from KTM Factory Racing efforts, making this the most READY TO RACE line-up yet.
The frame has received the most significant update share, with visible cutouts and tube-wall thickness changes around the front, engine mounts, and rear shock mounting areas. These changes have been specifically engineered to improve chassis flex characteristics and reduce weight by around 300 g while maintaining overall stability and improving cornering behavior. An updated swingarm with a machined chain glider and an updated rear brake pedal for improved durability round off updates to the frame.
New Dunlop GEOMAX MX34 Motocross tires are standard on the 2025 KTM SX and SX-F models, providing stability and control at the highest level to perform at their best. These feature a new carcass compound that improves damping and absorption, adding up to 30% longer performance. New Progressive Cornering Block Technology improves traction, grip, and mud dissipation.
At the rear, the WP XACT rear shock benefits from an updated linkage with renewed seals and smaller diameter linkage bolts. The setup is taken directly from the KTM Factory Racing Team and is optimized to benefit weight savings and stiffness parameters. To complement the updates at the rear, the WP XACT AER fork features reworked settings to account for more flex and less weight.
Ergonomically, the 2025 KTM SX and SX-F range features new tank shrouds with bi-composite plastics on the upper and lower flanks, providing a fresh, sharp, distinctive new look and improved cooling. This is supported by an updated fuel tank roll that protects the frame against wear from scrubbing and improves tank fitment. Lastly, an updated air inlet sleeve and snorkel design features on the 2025 models. This is now a 1-piece part, preventing deformation through a more robust and stiffer material design.
Above the surface, all-new graphics mirror the new design language of the tank shrouds and hint at the many small technical changes on the 2025 line-up. Full-orange bodywork, red and black in-mold graphics, and a more durable black seat bring a clean look while communicating pure, READY TO RACE intention.
2025 also sees the introduction of the Connectivity Unit Offroad, which is available as KTM PowerParts for the 2025 KTM SX-F line-up. The CUO offers various functionalities and adjustability options via the KTMconnect app. This exists as two parts: the CUO, mounted on the right upper fork between the lower and upper triple clamp, and the GPS sensor on the front fender. A CUO-compatible front fender is also available as a KTM PowerParts option.
At long last, the cherished KTM 150 SX rejoins the 2-stroke stable with much anticipation. The 2025 KTM 125 SX builds upon the foundation of the KTM 125 SX but with a significant overhaul of components. Specifically designed, modified, and rearranged for racers in pursuit of elevated performance, it offers enhanced torque and an enriched riding experience.
The 2025 KTM SX and SX-F models introduce subtle yet significant enhancements to the race paddock, offering the broadest selection of machines designed to meet the needs of every rider and racer.
2025 KTM 125 SX Totalmotorcycle.com Features and Benefits
NO JETS – ONLY ROCKET SHIPS
Electronic Fuel Injection
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.
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 125 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.
CLICK INTO ACTION
Easy Suspension Adjustment
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 control allows riders to adjust high- and low-speed settings in a matter of seconds. The forks on the front end are also easily adjusted thanks to hand-adjustable clickers on the bottom of the fork shoe and top cap.
Factory Performance Kit
Give your KTM 125 SX a more bite with a 125 Factory Performance Kit. Comprising of upgraded engine parts, a Factory expansion chamber, and special engine mapping, it provides a 2.5 hp increase while saving 15% of weight over the standard exhaust parts.
SMOOTHER POWER DELIVERY
EFI + Power Valve
With EFI comes great rideability. Along with the electronic fuel injection and a power valve on the KTM 125 SX, allowing for more usable power throughout the rev range. Smoother power means better traction. Better traction means holeshot heaven!
UNMATCHED PERFORMANCE
Performance
Designed to churn out torque the 2025 KTM 125 SX is set to continue its dominance in its class with unrelenting forward momentum. With an overall engine weight of only 17.86 kg and 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 2025 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.
SLEEKER FOR YOU TO SCRUB CLEANER
Absolute Control
Get ready for a full-on berm assault. The 2025 KTM SX and SX-F machines have received major frame updates directly from Factory Racing efforts. For starters, the frame area around the rear shock mount has been updated and made more streamlined, with new engine mounts and cut-outs for improved chassis flex. The front area of the frame is also updated. with a different wall thickness than the previous model year, with renewed engine mounts. This adds up to a 300g weight saving and improved flex for better cornering.
FLUID RIDER MOTION
Ergonomics
Upgraded tank shrouds using bi-compound plastics channel air towards the radiators more efficiently, while a new 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.
HARNESSING GRAVITY
Mass Centralization
With a major emphasis placed on mass centralization, the 2025 KTM 125 SX engine is designed to centralize rotating mass for optimal operation with the chassis. This results in a lighter, more agile handling feeling.
Updated Suspension Settings
For 2025, the KTM SX and SX-F range has given the WP XACT AER fork and WP XACT rear shock an update. This means you’ll be lining up at the setting gate with re-tuned settings, reduced weight, improved weight distribution, and an increase in overall response.
UNFLAPPABLE FRONT END
WP XACT Fork
Let’s get the technical parts out of the way first; the 48 mm WP XACT AER forks fitted to the 2025 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 boasts new settings, which not only compliment the updated 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 air pump needed to adjust the fork’s air pressure is provided as standard in the buy-pack.
WP XACT SHOCK
Keeping things in check at the rear, the WP XACT rear shock has also undergone some changes for 2025 using settings directly from the KTM Factory Racing Teams The improved frame and shock geometry mean more ground clearance at the linkage, making it less susceptible to bottoming out. While we’re on the topic, smaller diameter linkage bolts save weight, while new linkage seals refine rear shock response and advanced damping characteristics.
RACING ON RAILS
Stability
An upgraded rear brake pedal finds its way onto the 2025 KTM Motocross range, 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 2025 KTM Motocross range to the Dunlop GEOMAX MX34. Providing unmatched stability and control at the highest level, these rubber hoops feature a new carcass and rubber compound that improves damping and absorption, maintaining performance up to 30% longer. New Progressive Cornering Block Technology also improves grip in the berms, while a new rear pattern with 11% taller and 44% wider center block for increased traction and control everywhere else. Lastly, this unique block arrangement works to dispel mud buildup, ensuring traction in even the muddiest of track conditions.
PRECISE, LAP AFTER LAP
Consistency
A new chain guide and chain guard result in improved durability and minimize the chances of hooking on external objects – especially in extremely muddy conditions while reducing dirt build-up around the swingarm and rear sprocket.
UNOBTRUSIVE IMPACT
Energy absorption
Besides the expertly crafted, hydro-formed, laser-cut, and robot-welded frame being engineered to provide exceptional rider feedback and straight-line stability, it consists of specifically calculated parameters of longitudinal and torsional flex. This means the frame acts as a “shock absorber” of sorts, making for a less harsh ride, resulting in less rider fatigue over many hard laps.
NOTHING TO HOLD YOU BACK
Ground clearance
No one enjoys a bad hook-up. Good thing, then that the shock absorber geometry on the 2025 KTM 250 SX improves ground clearance of the linkage, with the topology-optimized die-cast footpegs being less susceptible to hooking on deep ruts, and take-offs when scrubbing.
2025 KTM 125 SX – Totalmotorcycle.com International Specifications/Technical Details
US MSRP Price: $8199 USD
Canada MSRP Price: $ 11449 CDN
Europe/UK MSRP Price: £8999 GBP (On The Road inc 20% Vat)
Engine
Transmission 6-speed
Starter Electric starter
Stroke 54.5mm
Bore 54mm
Clutch Wet multi-disc DS clutch, Brembo hydraulics
Displacement 124.8cm³
EMS Vitesco Technologies EMS
Design 1-cylinder, 2-stroke engine
Chassis
Weight (without fuel) 92.4kg
Tank capacity (approx.) 7.2l
Front brake disc diameter 260mm
Rear brake disc diameter 220mm
Front brake Disc brake
Rear brake Disc brake
Chain 520, Non-sealed
Frame design Central double-cradle-type 25CrMo4 steel
Front suspension WP XACT-USD (AER), Ø 48 mm
Ground clearance 359mm
Rear suspension WP XACT Monoshock with linkage
Seat height 958 mm
Steering head angle 63.9°
Suspension travel (front) 310mm
Suspension travel (rear) 300mm
Manufacturer Specifications and appearance are subject to change without prior notice on Total Motorcycle (TMW).
