It has been several years since the 125 SX has established itself as the queen motorcycle and the stepping stone to a professional career for young people. Powered by a high-performance two-stroke engine with exhaust valve and 6-speed transmission, the 2015 model year 125 SX has been further improved and will thus always attract the sympathy of young champions..
The engine of the 125 SX 2015 has been improved by an optimized ignition curve that allows more efficient combustion, for perfect power output and optimum handling.
The modern frame design of the SX models made of lightweight, high-strength chrome-molybdenum steel profile tubes combines maximum longitudinal stiffness with optimum torsional rigidity. On the new SX frame from 2015, a forged and milled cross tube connects the two halves of the frame and the draw rod of the idler mechanism. The absence of welds allows for extremely precise manufacturing tolerances and increased safety while saving 60 grams in weight.
Return mechanism / shock absorber
Redesigned for this 2015 model year, the damping system has a new return mechanism with optimized geometry. A more linear progression with a higher starting rate ensures increased stability while lowering the rear. In addition, this new design saves another 40 grams. Fully adjustable, the WP 5018 shock absorber has been perfectly optimized for this new return mechanism.
The fully adjustable WP Suspension upside-down fork has been perfectly matched to the rear shock absorber as well as the new 22mm front axle (up from 26mm so far) for the 2015 model year. The new axle provides better sensations in the front wheel while also reducing the weight by an additional 40 grams. The new front wheel axle mountings only feature a 33mm offset instead of 35mm, providing better stability with a higher caster angle. They also include new fork protectors that are 50 grams lighter..
The standard KTM equipment has for years included high-quality CNC-milled triple trees. They ensure precise handling and clearly emphasize the flex characteristics and therefore the responsiveness of the telescopic fork. New lower fork crown bearing O-ring bracket, overhauled tube and new steering head screw save another 40 grams.
The aim of the KTM designers was to create a more ergonomic and functional fairing, so that the whole bike down to the smallest detail was in perfect harmony with the rider. The molded plastic parts of the front mudguard are a model of solidity thanks to their sophisticated structure and attachment.
A new, more stylish graphic kit with clear lines underlines the uncompromising demands of this modern off-road motorcycle.
Perfectly ergonomic, the saddle contains a resistant foam core which provides greatly increased comfort and greater robustness..
The design of the air box guarantees optimum protection of the air filter against dirt, and maximum air flow for increased performance. Changing the Twin Air air filter in just a few seconds and without tools has long been standard at KTM.
All models in the SX range have a 7.5 liter lightweight polyethylene tank. The four-stroke motocross models feature the same fuel pump system as the four-stroke enduro models, allowing the optional installation of larger tanks available in the PowerParts catalog or on enduro models.
All SX models are fitted with a super strong Renthal Fatbar 827 tapered handlebar, the shape of which has been adapted to the demands of motocross. The proven KTM system allows the handlebars to be fixed in four different positions. The 2015 model has been fitted with softer two-component grips to preserve the rider’s hands.
When it comes to wheels, the 2015 version comes with black coated Excel rims with CNC machined lightweight hubs and spokes with lightweight aluminum nipples, to ensure maximum stability at minimum weight. The new Dunlop Geomax MX 52 tires were designed in collaboration with the KTM USA factory team and offer optimal traction and top performance. The new crowns save another 50 grams on the unsprung masses.
High-tech Brembo brakes have long been standard on KTM off-road motorcycles with lightweight wave disc brakes for optimum braking performance. Best brakes in their category in motocross, they remain unchanged on this 2015 version.
Info credit: KTM
Image credit: KTMimages
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125 SX 2014
Model marketed in
The technical aspect
KTM 125 SX 2015
- Tank: 7.5 liters
- Wheelbase: 1,480 mm
- Dry weight: 90 kg
- Train before
- Secondary chain transmission
- Rear axle
(54 x 54.5 mm)