50 SX – 2025

When the next step up is into the 50cc class, there is no better option than the most powerful 50cc out there. For 2025, the KTM 50 SX is built around an advanced steel frame, housing a powerful engine, a 35mm WP XACT AER fork, a WP XACT monoshock, and an advanced hydraulic Formula brake system. Simply put – it’s the most advanced and READY TO RACE 50 cc mini-crosser available to your little racer.

ADJUSTABILITY
Different adjustability options were built into the 2025 KTM 50 SX construction using scientific statistical data and young racers’ input data. Finding the right fit for your little ripper is easy thanks to height-adjustable suspension, handlebar position, subframe, and bodywork, taking the seat height from a low setting of 634mm to a taller setting of 682mm. 

IGNITION
Fitted with a digital ignition the with improved processing power making for a cleaner burn and smoother power delivery. Individual ignition timing across the entire rpm range, just like that found on the full-sized KTM SX range, adds a key advantage.

CARBURETOR
A proven Dell’Orto type PHBG 19 BS carburetor takes a prime position in producing the goods in the 2025 KTM 50 SX, that works perfectly in harmony with the engine, exhaust, and air intake design. 

PERFORMANCE
The 2025 KTM 50 SX features a modern and compact engine using the latest 2-stroke technology. Using a 3-shaft design, the crankshaft is positioned near the center of gravity, which not only benefits mass centralization but also creates the ideal intake angle into the reed valve for top-level performance. An independent cylinder blank allows for a completed cylinder design, with increased power. 

POWER-REDUCTION KITS
For absolute beginners, the KTM POWERPARTS catalog offers a choice of two power-reduction kits. The first allows for a entry-level, moderate and controllable power reduction to 4hp, with the second allowing for a more intermediate power kit unleashing 8hp for mid-level riding levels.

CLUTCH
The 2025 KTM 50 SX is fitted with a centrifugal clutch reducing the complexity for younger riders, and helping to boost riding confidence. The multi-disc clutch delivers a precise and predictable power delivery across the RPM range. It can be set to suit rider preferences or track conditions without using any special tools. Also, a reinforced clutch basket provides Improved durability, wear, and consistent performance. 

SPARK PLUG
There’s no more worrying about breaking the plug, thanks to the 2025 KTM 50 SX featuring a spark plug from BRISK with a longer thread. Also, thanks to this innovation from BRISK, the part number is printed on the spark plugs for easy reading. 

TANK
The KTM 50 SX is ready to fuel the fire in your little ripper with a tank design that compliments the frame and bodywork. 

AIRBOX AND FILTER
The airbox features a conventional suction sleeve made from a hard-wearing polyamide instead of rubber and a Twin Air filter mounting system that features snap locks for easy and intuitive mounting. The Twin Air filter is also placed under the seat and is easily accessible without any tools by simply removing the seat. It also features improved dirt intrusion resistance, with no more dirt falling into the intake tract when changing the filter.

ERGONOMICS
Mimicking the full-size KTM SX range, the KTM 50 SX features the same advancements found in the larger KTM SX range. Slimmer, sleeker, and better suited to standing on the pegs, the side panels now work much better with young riders’ boots, allowing a proper squeezing of the bike when standing up. The front number plate incorporates plastic flaps to protect the lower triple clamps from roost, while the tank spoiler features a bicomponent technology featuring the KTM-specific texture on the upper part. Side number plates are kept as close to the frame as possible, with the general seat line sitting slightly flatter. 

HANDLEBARS AND GRIPS
Hold on tight! The high-quality, tapered, black handlebar is made of lightweight aluminum alloy and ensures top stability, vibration damping, and control. The bend and profile is designed specifically to meet the needs of young riders, with ODI grips on the left, and a vulcanized ODI grip on the right-side throttle assembly, adding to the overall quality. A crash pad on the handlebar protects the rider from any rough contact or impact with the bars. 

FRAME
Right, this is a big one. The 2025 KTM 50 SX boasts a high-strength chromium molybdenum steel frame design with forged connecting parts integrated into the frame. This together with carefully calculated parameters of longitudinal flex and torsional rigidity, allow tailormade stiffness and an unprecedented quality of the Mini frame could be achieved. The frame layout features a typical MX design without any cross tube behind the steering head. Like our full-size models, the rear shock mount is separated from the main upper frame tube. The frame also comes with frame protectors as standard. 

WHEELS AND TIRES
Rolling off the race rig and into the pit lane, the 2025 KTM 50 SX uses lightweight, black anodized, aluminum rims just like the full-size KTM SX range. These provide the highest levels of strength and reliability, while MAXXIS MX-ST tires deliver outstanding performance on any terrain, along with exceptional straight-line stability. 

FOOTPEGS
A “no-dirt” footrests offer a bigger surface area for improved grip while standing on the pegs, and are less susceptible to hooking up in deep ruts, take-offs when scrubbing, or track barriers. 

SUSPENSION
Featuring the latest in suspension technology, the KTM 50 SX is fitted with a state-of-the-art, lightweight 35mm USD WP XACT AER fork. With 205mm of wheel travel, the air unit in the left fork leg can also be adjusted easily using an air pump for rider preference, rider weight, or track conditions. At the rear, a fully-adjustable WP XACT monoshock boasts mounting points on the frame, making it more compact, and providing the perfect balance and damping characteristics to match the fork. 

BRAKES
Featuring the same level of technology offered on the full-size KTM SX range, the 2025 KTM 50 SX is fitted with hydraulic brake calipers and state-of-the-art front and rear waved brake discs. This system ensures advanced braking feel and unmatched stopping performance in all conditions, specifically on wet or muddy tracks, with improved durability and brake pad longevity. 

EXHAUST
The exhaust system, features the same manufacturing process as the full-size 2-stroke KTM SX range, with improved overall quality and performance. This has resulted in massive improvements in thermodynamics. Moreover, improved sealing of the silencer end cap and a rubber between the header pipe and silencer adds another level of quality to the exhaust system. The silencer comes with a black anodized finish and a signature ‘Braaaaap!’. 

RADIATOR
Featuring state-of-the-art technology and superior cooling power, the 2025 KTM 50 SX uses one large radiator with more capacity instead of two smaller separate ones. This concept allows for better integration of the radiator into the frame and the tank spoilers to channel air through the cooling fins efficiently. 

HOUR METER
Keep track of engine hours easily, with an hour meter mounted at the same position behind the front number plate – as on the full-size KTM SX models. This makes for easier reading and has a lower risk of dirt and water fowling up the display. 

GRAPHICS
Modeled after the full-size motocross bikes, the KTM 50 SX features typical READY TO RACE graphics using the time-proven in-mold application process to ensure the best durability and quality.