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2021 KTM 50 SX [Model Overview]

2021 KTM 50 SX

The 2021 KTM 50 SX: Young Motocross Bikes For The Beginner

The 2021 KTM model range for the 50 SX includes three bikes, all powered by the same engine: The 50 SX-Mini, the 50 SX, and the 50 SX Factory Edition. The 49cc two-stroke engine produces just about 5.5 HP, more than enough to get the young motocrosser some airtime without sending them into the stratosphere.

KTM is an Austrian company that has always been about off-road bikes from the very outset, so it is no surprise that they make a young riders edition of their successful two-stroke motocross bikes. The smallest, the 50 SX-Mini, is designed for kids as young as 4 or 5 to get on the bike and learn the ropes of off-road riding. The 50 SX is designed for slightly older children, maybe aged 7 or 8. And the 50 SX Factory Edition takes that 50 SX and throws parts specially developed by KTM’s racing partners onto it to make it a bonafide, top-tier junior motocross bike.

KTM, with its Motocross experience, doesn’t shy away from racing parts on the other two models, however. All three are equipped with WP XAct suspension front and rear, as well as full disc brakes front and rear. Where the Factory Edition differs is in the exhaust, made by FNF Racing, the tires, being race-proven Dunlop Geomax MX 53’s, and by having a clutch lever, which is attached to a single-speed automatic transmission, but allows the rider to determine when it engages.

The 2021 KTM 50 SX-Mini starts at $3,899 USD / $4,549 CAD, the 50 SX at $4,399 USD / $4,949 CAD, and the 50 SX Factory Edition at $5,199 USD / $5,999 CAD.

On this page: we’ve curated specs, features, news, photos/videos, etc. so you can read up on the new 2021 KTM 50 SX in one place.

2021 KTM 50 SX

Model Overview

General Info

  • Price: $3,899 USD / $4,549 CAD
  • Key Features:
    • Single speed automatic transmission, twist-and-go
    • WP XAct motorsports grade suspension
    • Special Factory Edition comes ready-to-race out of the crate

Main Specs

  • Engine Type: 49cc two-stroke single
  • Horsepower: 5.5 HP
  • Torque: Not provided by manufacturer
  • Wet Weight: 88 lbs (40 kg)
  • Seat Height: Not provided by manufacturer

2021 KTM 50 SX

2021 KTM 50 SX Specifications

From KTM


Engine 49cc , 1-cylinder, 2-stroke engine
Power 5.5 HP
Bore x Stroke 40 mm x 39.5 mm
Power in KW
Starter Kickstarter


Clutch Centrifugal clutch (adjustable)
Transmission Single-speed automatic
Chain 1/2 x 3/16″


Suspension Front XACT 35 WP Upside-Down fork, Ø 35 mm
Suspension Rear XACT WP mono shock
Brakes Front 160 mm, Disc brake
Brakes Rear 160 mm, Disc brake
Suspension travel (front) 205 mm
Suspension travel (rear) 185 mm
Tank capacity (approx.) 2.3 l
Color Black, Orange


Spark Plugs
Headlight LED
Tail Light LED


Overall Length
Overall Width
Overall Height
Ground Clearance 252 mm
Seat Height 684 mm
Wet Weight 41.5 kg



2021 KTM 50 SX

2021 KTM 50 SX Features


The high performance cylinder, exhaust pipe and reed intake system are perfectly arranged for maximum performance, setting the standard in the highly competitive 50 cc class.

Power reduction kit

For those future stars who are still absolute beginners, the engine power can be reduced using a kit from the PowerParts program.


Developed by KTM, the centrifugal multi-disc automatic clutch provides manageable acceleration and makes riding this motorcycle as easy as twisting the throttle. It can be adjusted to the specific requirements of the track and the rider in minutes and without any special tools.


Like the full-size KTM range, the 50 SX has a liquid cooling system, which even cools the crankcase. Generously sized radiators ensure outstanding heat dissipation, ensuring extra reliability, even under extremely heavy conditions.


The exhaust system was designed to perfectly match the characteristics of the engine, ensuring maximum output and a smooth power delivery over the entire rev range.


The modern frame is made from lightweight, high strength chromoly steel profiles and combines maximum longitudinal stiffness with optimum torsional rigidity. It guarantees easy handling and precise cornering, but also outstanding stability.


The 50 SX is fitted with front and rear hydraulic brakes by FORMULA, combined with lightweight wave discs that are easy to control even for the youngest riders. This ensures the best deceleration and the highest standard when it comes to performance.


Like the full-size KTM Factory racers, the 50 SX has super lightweight, black anodized, aluminum rims providing the highest strength and durability. The OEM MAXXIS knobby tires grip superbly on any surface.


The KTM 50 SX uses a perfectly shaped handlebar made from a high-quality aluminum alloy. It provides a great feeling of control for the rider, helping with overall stability. A pad around the center brace also protects the rider from hard knocks.

2021 KTM 50 SX Photos

2021 KTM 50 SX Videos