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Motocross Bikes

2019KTM 125 SX

★ 4.0
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The 2019 KTM 125 SX is a lightweight two-stroke motocross bike engineered for young and junior riders seeking competitive performance. Known for its aggressive styling, nimble handling, and responsive power delivery, it excels in amateur racing and recreational off-road riding. WP suspension and precision CNC components ensure precise control across varied terrain.

Capacity
124.8 ccm
Engine
Single, two-stroke
Gearbox
6-speed
Dry weight
87.5 kg
Seat height
950 mm
Power
15.0 HP (11.0 kW)
⇄ Compare with another bike + Add to garage All model years

What’s new for the 2019 KTM 125 SX

vs the 2018
Spec20182019
Seat height 960 mm (37.8 inches) 950 mm (37.4 inches)
Fuel capacity 7.00 litres (1.85 US gallons) 7.50 litres (1.98 US gallons)
Other years 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2025 2026 2027

How it rides

Editorial estimate from the spec sheet - not lab tested
Speed 48Agility 90Comfort 25Off-road 96Touring 10Road manners 15
Off-road & trail96%
Cornering90%
City riding10%
Daily riding10%
Touring8%
Two-up5%
Track95%
Best for
Built purely for closed-course motocross racing, it excels at jumps, berms, and rapid direction changes on dirt tracks rather than any street use.
Built for
Light, explosive, and razor-sharp in handling, it rewards aggressive riding with a peaky two-stroke power band and minimal weight to manage.
Not ideal for
It is not suitable for commuting, highway travel, passengers, or riders seeking comfort, storage, or a forgiving low-end power delivery.

Scores are derived from the spec sheet using the same model across every bike, so they compare like for like.

Will it fit you?

Worked out in your browser - nothing is sent to us
At 950mm, a rider of 68.9" with a 31" (estimated) inseam will not reach the ground comfortably on the 2019 KTM 125 SX, with a cramped knee angle of around 85 degrees and an upright riding position.

Assumes about 30mm of suspension sag once seated. This is an approximation from category-typical geometry, not a measurement of this bike or of you - sit on one before you buy.

More bikes at over 900 mm — Sky High →

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Full specifications

Engine
Capacity
124.8 ccm
Power
15.0 HP (11.0 kW)
Engine type
Single, two-stroke
Power/weight ratio
0.1714 HP/kg (dry)
Bore x stroke
54.0 x 54.5 mm
Cooling system
Liquid
Fuel system
Carburettor
Starting
Kick
Ignition
Kokusan EMS
Lubrication system
Wet sump
Transmission
Gearbox
6-speed
Transmission type
Manual
Final drive
Chain
Clutch
Wet multi-disc clutch, hydraulically actuated
Dimensions & weight
Wheelbase
1485 mm
Seat height
950 mm
Dry weight
87.5 kg
Fuel capacity
7.50 litres
Ground clearance
375 mm
Chassis & suspension
Frame
Chrome-molybdenum steel central-tube frame
Front suspension
WP-USD, AER 48, Ø 48 mm
Rear suspension
WP shock absorber with linkage
Front wheel travel
310 mm
Rear wheel travel
300 mm
Rake (fork angle)
26.1°
Trail
120 mm
Brakes & wheels
Front brakes
Single disc. Brake calipers on floating bearings
Front brakes diameter
260 mm
Rear brakes
Single disc. Brake calipers on floating bearings
Rear brakes diameter
220 mm
Front tyre
110-17
Rear tyre
150-17
Other
Color options
Orange/white/black

Compiled from manufacturer documentation and user contributions, corrected on an ongoing basis. Spotted something wrong? Tell us.

What changed, year to year

Differences highlighted
Specification 200320092015201920202027
Capacity 125 cc 125 cc 125 cc 125 cc 125 cc 125 cc
Dry weight 94 kg 91 kg 91 kg 88 kg 88 kg 92 kg
Seat height 925 mm 985 mm 992 mm 950 mm 950 mm 958 mm
Fuel capacity 7.5 L 8 L 7.5 L 7.5 L 7.5 L 7.2 L

Illustrative - generated automatically by diffing the year records already on file, not a manufacturer-published changelog.

Rider Reviews

4.0
★★★★☆
Rider rating
MotorcycleDB

The 2019 KTM 125 SX is a top-tier motocross bike that offers a winning combination of power, agility, and durability. This lightweight and nimble machine is perfect for riders looking to dominate the track with its advanced 2-stroke engine and race-ready suspension. The sleek and eye-catching design is complemented by top-of-the-line components, making it a standout choice for both amateur and professional riders.

Overall, the 2019 KTM 125 SX is a fantastic choice for motocross enthusiasts who are seeking a high-performance and reliable bike. With its impressive power, precise handling, and top-notch construction, it's no wonder this model has become a favorite among riders who demand the best from their machines. Whether you're hitting the trails or competing on the track, the 2019 KTM 125 SX is sure to deliver an unbeatable riding experience.

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Common questions

What is the engine size of the KTM 125 SX?

The 2019 KTM 125 SX has a Capacity of 124.8 ccm (7.62 cubic inches).

What engine power does the KTM 125 SX have?

The 2019 KTM 125 SX has a Power of 15.0 HP (11.0 kW).

How many gears does the KTM 125 SX have?

The 2019 KTM 125 SX has a Gearbox of 6-speed.

How much does the KTM 125 SX weigh?

The 2019 KTM 125 SX has a Dry weight of 87.5 kg (192.9 pounds).

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