KTM is not a company that plays follow the leader. Instead of piggybacking on other company’s popular designs, KTM has a reputation for going its own way and building bikes that stand out from the crowd. The 2009 KTM SX is a great example of this philosophy. While most companies have abandoned two-stroke motorcycles in favor of four-strokes, KTM instead decided to engineer a powerful two-stroke dirt bike that is capable of competing with other companies’ four-stroke models both on the dirt track and in the marketplace. When the American Motorcycle Association (AMA) decided to let two-strokes compete in their four-stoke amateur competitions, KTM was quick to design and release the 150SX. When the AMA expanded the 250cc amateur class to include two-strokes, KTM was once again on the cutting edge of releasing a 250cc two-stroke, capable of competing against the four-strokes.
Instead of just following the stampede towards four-stroke motocross bikes, with the SX, KTM has delivered a high-performance two-stroke that embodies modern engineering. The Austrian company offers three versions of the SX: a 150cc version, a 250cc version, and a 450cc version. These engines represent the pinnacle of two-stroke engine performance, being liquid cooled and featuring a TVC power valve.
The 2009 KTM SX150cc generates 40 peak horsepower, which is a respectable amount of power for a motocross bike, since it is so light in weight. The 250cc SX produces 49 horsepower at peak, and the largest 450cc SX reaches 53 horsepower. These numbers are competitive with the four-stroke bikes that the SX competes against. The power band on the KTM SX bikes is seamless, with a focus on mid- and high-range rpm power, which makes them suitable for motocross events, although more casual riders can certainly enjoy this performance on weekend dirt bike rides. The new for 2009 Keihin PWK 38 carburetor efficiently delivers fuel to the engine and is more reliable than the previous year’s carburetor.
An excellent power-to-weight ratio is achieved by KTM’s clever chassis design. A central double cradle aluminum frame forms the basis of a well-balanced chassis, with lightweight Renthal aluminum handlebars that create a comfortable riding position. This design allows the SX models to make the most of the horsepower and torque that is available.
Handling on a competitive motocross bike is extremely important, and it's clear that KTM engineers recognize this fact. The 150cc SX has an excellent power-to-weight ratio that is perfectly suited for KTM’s single shock, no linkage suspension system. With excellent ergonomics designed to enhance the rider’s control over the bike, the bike’s light weight, and a rear wheel travel of 11.8 inches in front, the SX models can handle the most rigorous motocross track with ease. Combined with the excellent throttle response of the two-stroke engine, the SX is capable of nimbly changing directions and is limited only by the skill of the rider. Overall, the SX offers excellent maneuverability that many four-stroke bikes cannot match.
When it comes time to slow down and stop, KTM has that covered as well. Using a 260mm disc in front, with a 210mm disc in rear, the SX has excellent stopping power. The 250SX uses top-end Brembo brakes that have a reputation for reliability. The SX is certainly not a bike where the rider ever has to worry about the brakes failing.
The 2009 KTM SX comes in KTM’s iconic black and orange color combination. Perhaps most interesting is that KTM uses molded-in graphics. With this clever implementation, after a simple wash, the bike will look as crisp as it did when it was brand new. Whether you are looking for a motocross bike that is different from your friend’s bikes, or you value the nostalgia of the heyday of two-strokes, the KTM SX offers a great ride.