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Reviews/ Ktm/ Sx 125
WATCH REVIEW
8.5/10 Motocross

Ktm Sx 125 Review

"An uncompromising race tool that rewards preparation and serious skill."

Experienced motocross riders wanting genuine race performance $3,500-$6,500 used 2016-2023
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Key Specs

speed
Top Speed
~110 km/h (estimated; top speed varies significantly based on gearing and track conditions)
bolt
Power
~34 hp
@ 11,500 rpm (estimated for modern 2020+ era models)
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Torque
~25 Nm
@ 10,500 rpm (estimated)
local_gas_station
Fuel Economy
25.0 km/L
59 mpg ยท Estimated 4โ€“6 L/100km (note: varies greatly depending on riding intensity; two-stroke motocross bikes are not typically measured by standard fuel economy metrics)
build
Service Every
15 hours (motocross use)
scale
Weight
~98 kg
(wet/curb weight, based on 2020+ models)
settings
Engine
124.8cc single-cylinder 2-stroke
height
Seat Height
960 mm
cog
Transmission
6-speed
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Used Buyer Review

The KTM SX 125 is genuinely one of the best two-stroke motocross bikes ever built, but buying one used is a serious exercise in due diligence. These engines live hard and die young in the wrong hands. Before handing over any cash, pull the pipe and inspect the power valve โ€” gunk buildup tells you everything about how it was maintained. Check the reeds, ask for rebuild receipts, and budget another $500-800 regardless because something will need attention. When it's right, this thing is electric. The chassis is razor-sharp, the WP suspension punches well above its class, and that screaming 125cc two-stroke pulls harder than the displacement suggests once it hits the powerband. It rewards skilled riders massively but will punish anyone who hasn't earned their spurs on a proper dirt bike. Suspension setup matters enormously โ€” a previous owner's spring rates might be completely wrong for your weight. Priced sensibly, a well-maintained example is outstanding value. But inspect ruthlessly, and walk away from anything that looks neglected.

Pros

+Razor-sharp race chassis
+Exceptional power-to-weight ratio
+Premium WP suspension
+Lighter than four-strokes
+Huge aftermarket support

Cons

-High maintenance demands
-Brutal, unforgiving powerband
-Frequent top-end rebuilds
-Parts costs add up
warning
Avoid if

You're a beginner or hate wrenching

description View full specs, facts & rivals for Ktm Sx 125 โ†’

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