The 2021 KTM 125 SX: Introduction To The Big Leagues
The KTM 125 SX is what KTM themselves call the first bike to buy to start your racing career. This 2021 model is a pure racing machine, built with a lightweight chassis and frame cradling a 125cc two-stroke single. That little screamer of a thumper pushes out 37.5 HP, which is the most of any 125cc two-strokes on sale today by the European manufacturer.
KTM then gets down to business. A grippy race seat is fitted, which is also quite comfortable for longer distances in cross-country races. A NEKEN racing aluminum handlebar is then fitted, and a lightweight KTM racing exhaust allows for little to no backpressure, letting the engine breathe freely as it needs to.
WP suspension has been fitted to the bike, as with all their competition bikes. The clutch is a multi-plate unit with reliable Brembo hydraulics. The full size wheels are fitted with competition grade Dunlop GeoMax MX 3S tires, everything you’d expect from KTM Motorcycles. A truly unique feature of the 125 SX is that if the footpegs are too low, they are interchangeable with the footpegs from the 350 EXC-F, which sit half an inch higher.
The 2021 KTM 125 SX starts at $7,399 USD / $8,799 CAD.
On this page: we’ve curated specs, features, news, photos/videos, etc. so you can read up on the new 2021 KTM 125 SX in one place.
- Price: $7,399 USD / $8,799 CAD
- Key Features:
- 6-speed manual transmission
- WP XAct racing suspension included
- Kickstarter only, no electric start
- Engine Type: 125cc two-stroke single
- Horsepower: 37.5 HP
- Torque: Not provided by manufacturer
- Wet Weight: 208 lbs (approx 94.5 kg)
- Seat Height: Not provided by manufacturer
2021 KTM 125 SX Specifications
|Engine||125cc, 1-cylinder, 2-stroke engine
|Bore x Stroke||54 mm x 54.5 mm|
|Power in KW|
|Clutch||Multi-plate clutch, Brembo hydraulics|
|Chain||5/8 x 1/4″|
|Suspension Front||WP XACT-USD, Ø 48 mm
|Suspension Rear||WP XACT Monoshock with linkage
|Brakes Front||260 mm,
|Brakes Rear||220 mm, Disc brake
|Suspension travel (front)||310 mm|
|Suspension travel (rear)||300 mm|
|Tank capacity (approx.)||7.5 l|
|Ground Clearance||375 mm|
|Seat Height||950 mm|
|Wet Weight||87.5 kg|
2021 KTM 125 SX Features
Crankcases and engine covers
2021 KTM 125 SX Photos
2021 KTM 125 SX Videos