KX450 (MY2019)

Kawasaki built this KX450 generation as a race tool, and the hardware shows it. A 449 cc liquid-cooled single with fuel injection sits in an aluminum perimeter frame. It makes 57 hp and responds crisply to the throttle. Up front is an upside-down coil-spring fork, and it adjusts just like the shock does, so you set it up with clickers and springs instead of fiddling with air pressure. Kawasaki adds launch control and selectable ride modes. On the start line and when the dirt changes, those are real tools, not gadgets. This is an honest, no-nonsense 450 that gets the basics right and leaves you free to focus on the moto.

At 243 lb (110 kg) wet, it changes direction with less effort than a big single usually needs. The chassis is built to take a beating, and aftermarket support is deep, so a used example is easy to freshen up and make your own. This bike is for the rider who races or trains seriously on a prepared motocross track. The honest caveat is that there's no traction control, so finding drive on slick ground is up to your right wrist. The plastic rear shock preload collar is also fragile. Inspect it on any used bike and treat it gently every time you set sag.