How Much Horsepower Does The Kawasaki KX450 Have & How Fast Can It Go?
Kawasaki's first foray into motocross dates back to 1963, but Kawasaki's ultimate motocrossers didn't become known by the KX badge until 1975. Currently, Kawasaki KX dirt bikes include sizes like 65, 85, 112, 250, and 450. Kawasaki 65, 85, and 112 cc models use liquid-cooled two-stroke single-cylinder engines, while the 250 and 450 are also liquid-cooled single-cylinder but feature four-stroke technology.
Motocross Action Magazine (MXA) tested the 2025 Kawasaki KX450 last year. During the MXA YouTube video, Josh Mosiman discusses the KX450 testing revealed dyno-testing showing the bike's 449cc engine produced 57.2 horsepower.
While that's not as much power as some of the competitor's 450s, Mosiman claims the KX450's power is "very mellow." Mellow power combined with the KX450's relatively heavy 239 pounds doesn't sound like a great combination for a motocross racing bike, but its neutral rider triangle with adjustable foot pegs and handlebars make it easy to get comfortable.
On the top end, the KX450 is pretty fast for a dirt bike. Video evidence posted on YouTube by Two Wheel Turban reveals a GPS-measure top speed of 83 mph aboard a KX450. Another KX450 speed test video by Benn Hollinger reveals GPS speeds up to 94 mph. Both KX450 dirt bikes are said to be stock with stock gearing.
Is the KX450 a good dirt bike?
The Kawasaki KX450 is a good dirt bike with several American Motorcyclist Association (AMA) motocross and supercross titles among its accolades, with riders like James Stewart, Ryan Villopoto, and Eli Tomac being some of the most recent to make history aboard the KX450. During the 2024 AMA Motocross Racing season, Jason Anderson rode the number 21 Kawasaki KX450 to fifth place in the premier class points standings at the end of the season.
Jason Anderson's highly modified KX450 isn't like the production model sitting on the local Kawasaki dealership's sales floor. However, the standard KX450 features selectable power modes, launch control, Kawasaki traction control, smartphone engine mapping, Brembo brake components, and Showa front forks. The KX450SR has an upgraded triple clamp and Pro Circuit Titanium Exhaust.
The KX450 and KX450SR are designed for motocross and supercross racing. However, the KX450X is better suited for cross-country trail riding and racing. While the KX450X features many of the same features as the KX450, including customizable engine mapping, traction control, power modes, and Brembo brake components, its suspension settings are tuned for trail riding versus conditions found on motocross and supercross tracks.