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FULL-SCREAM AHEAD

2025 KTM 125 SX

2025 KTM 125 SX

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  • Base Price: 10,499.00 EUR*

*inc VAT, delivery to dealer and PDI

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*inc VAT, delivery to dealer and PDI

SHOW MORE
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.

This motorcycle is designed, developed and produced in Austria.
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.

This motorcycle is designed, developed and produced in Austria.
  1. Before The Gate
  2. Start Strong
  3. Calm Under Fire
  4. Hit The Big Stuff
  5. Maintaining Momentum
Before The Gate

01. Before The Gate

Before The Gate
NO JETS - ONLY ROCKET SHIPS
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.
NO JETS - ONLY ROCKET SHIPS
Before The Gate
CHUGGA CHUGGA, RING DING DING!
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 r ...
CHUGGA CHUGGA, RING DING DING!
Before The Gate
CLICK INTO ACTION
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 mat ...
CLICK INTO ACTION
Start Strong

02. Start Strong

Start Strong

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 exh ...
Start Strong
SMOOTHER POWER DELIVERY
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!
SMOOTHER POWER DELIVERY
Start Strong
UNMATCHED PERFORMANCE
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 r ...
UNMATCHED PERFORMANCE
Start Strong
PICK YOUR POWER
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 powe ...
PICK YOUR POWER
Calm Under Fire

03. Calm Under Fire

Calm Under Fire
SLEEKER FOR YOU TO SCRUB CLEANER
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 streamlin ...
SLEEKER FOR YOU TO SCRUB CLEANER
Calm Under Fire
FLUID RIDER MOTION
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 dura ...
FLUID RIDER MOTION
Calm Under Fire
HARNESSING GRAVITY
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.
HARNESSING GRAVITY
Hit The Big Stuff

04. Hit The Big Stuff

Hit The Big Stuff

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 ...
Hit The Big Stuff
UNFLAPPABLE FRONT END
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 ...
UNFLAPPABLE FRONT END
Hit The Big Stuff

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, m ...
Hit The Big Stuff
RACING ON RAILS
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 ...
RACING ON RAILS
Hit The Big Stuff

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 fea ...

05. Maintaining Momentum

PRECISE, LAP AFTER LAP
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.
PRECISE, LAP AFTER LAP
UNOBTRUSIVE IMPACT
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 ...
UNOBTRUSIVE IMPACT
NOTHING TO HOLD YOU BACK
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 ...
NOTHING TO HOLD YOU BACK

Technical Details

Engine

  • Transmission 6-speed
  • Starter Electric starter
  • Stroke 54.5 mm
  • Bore 54 mm
  • Clutch Wet multi-disc DS clutch, Brembo hydraulics
  • Displacement 124.8 cm³
  • EMS Vitesco Technologies EMS
  • Design 1-cylinder, 2-stroke engine
  • Fuel-mixture generation Keihin EFI, throttle body 39 mm

Chassis

  • Weight (without fuel) 92.4 kg
  • Tank capacity (approx.) 7.2 l
  • Wheelbase 1493 mm
  • Front brake disc diameter 260 mm
  • Rear brake disc diameter 220 mm
  • 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 359 mm
  • Handlebar Neken, aluminium Ø 28/22 mm
  • Rear suspension WP XACT Monoshock with linkage
  • Seat height 958 mm
  • Silencer Aluminium
  • Steering head angle 63.9 °
  • Rear subframe design Aluminum-reinforced polyamide
  • Suspension travel (front) 310 mm
  • Suspension travel (rear) 300 mm
  • Wheels Spoked wheels with aluminium rims