Four-stroke dirt bikes used for motocross and supercross racing max ... any 250-, 300-, 450-, or 500cc dirt bike could exceed 100 mph — making the large knobby tires' tenuous grip on whatever ...

At $9,799, the 250XC offers you a dirt bike with an ungraded frame that results in exceptional handling and straight-line stability. These motorcycles are also equipped with an air boot and airbox ...

The 250 RX is a long-stroke motor, while the 350 RX is a short-stroke mill. Despite that, the 250 delivers “explosive ...

These new additions join the returning 450 RX 4-stroke in Beta’s RX lineup, delivering fresh options for racers and dealers as the brand continues to make inroads in the U.S. motocross scene.

Husqvarna’s TE250i is a fuel-injected two-stroke dirt bike, with an electric start, that could change the face of trail and enduro riding. (Charles Fleming / Los Angeles Times) By Charles Fleming ...

In dirt bike racing, two-stroke and four-stroke engines have their own unique advantages. ... Given the right ratio final drive, any 250-, 300-, 450-, or 500cc dirt bike could exceed 100 mph ...