First Impression: 2004 KTM 125 SX—That Old Familar Buzz

TransWorld Motocross and the rest of the motorcycling press converged en masse on Cahuilla Creek MX Tuesday, all eager to spend a day trying out the latest models from KTM. TWMX testers got to put in laps on the full range of KTM’s moto offerings, including the 250 SX, 450 SX, and 525 SX. For right now we’ll focus on the KTM125 SX.


While lots of interest has been directed toward the yet-to-arrive ’04 250cc four-strokes from the Japanese manufacturers, KTM is plenty happy to keep attention focused on their 125cc two-stroke screamer, which has always been one of the horsepower leaders in the tiddler class. Refinements to the ’04 125 SX add a couple horsepower to their already potent mill. Goodies like a V-Force intake system provide improved throttle response and more peak power, along with a new pipe that’s designed to boost mid-range and top end.

While the changes to the engine fall under the category of refinements, more attention was directed towards the chassis, suspension, and ergonomics. The wall thickness on the chromoly frame has been reduced for lower overall weight, though the steering head received additional reinforcement. KTM claims that the frame now tips the scales at less than 20 pounds.

A lot of attention was also paid to reducing flex at the swingarm pivot of the various models, with a new forged swingarm support. The diameter of the swingarm pivot was also increased by 2mm to 17mm. A 10mm longer swingarm was added on all 2004 models in the quest for more traction along with additional room for the rear wheel.

WP suspension components grace both ends of the 125 SX, and the quest for both ends was more progressive action. The shock got lots of attention, with the focus on bottoming resistance, and a linear-wound main spring.

You can expect to find a little more comfort in ’04, with taller Renthal bars, a seat that isn’t as tough, and flatter profile footpegs similar to the ones found on last year’s 250 SX 2003.


Riding the 125 SX was a blast. As you’d expect, the quantity of power was excellent for a 125, pulling hard over a respectably wide range. Shifting was excellent, aided as always by the buttery-smooth hydraulic clutch.

The suspension tracked well on both ends even late in the afternoon when square-edged bumps starting showing up around the track, and the Bridgestone M 59 and M 70 tires worked well on both the wet and powdery sections of Cahuilla Creek.

When it came time to bring things to a halt, none of the TWMX testers had any complaints, but they all raved about the performance of the front brake.

Look for a more complete report on the KTM 125 SX in an upcoming issue of TWMX, but in the meantime, click the link on the right at the top of this page for a video of our day at Cahuilla Creek.