Dirt Rider Magazine covers the latest in dirt bikes and off-road motorcycle racing, including Motocross, Enduro, Supercross, MotoTrials, and more. Read all about the latest in dirt bike racing, including information on race results and upcoming motocross racing events. Extreme Top Fuel Motorcycle Dirt Drag Shoot Out. I wonder if the ppl that ride these bikes r nervous before. Throughout the United States and the United Kingdom there are many quad racing clubs with enduro and quadcross sections. Dirt Bike Sizes  The most common dirt bike sizes are 50cc, 70cc, cc, cc, cc and cc. Ambulance Blood Fire Police. Copyright Motorcycle USA, LLC. Ossa Spain Polini Italy Pitster Pro United States Stallions Thailand Thumpstar Australia Viar Indonesia. The intense competition over rugged terrain led to technical improvements in motorcycles. Reviews Ride Style Cruiser Dirt Bike Sportbike Street Bike Scooter Touring Manufacturers Aprilia Motorcycles BMW Motorcycles Ducati Motorcycles Harley-Davidson Motorcycles Honda Motorcycles Indian Motorcycles Kawasaki Motorcycles KTM Motorcycles Suzuki Motorcycles Triumph Motorcycles Yamaha Motorcycles Motorcycle Manufacturers Racing Features Events Interviews Backmarker Memorable Motorcycles Single Track Mind Dr. Check out video highlights from the Southwick National, Round 7 of the Pro Motocross Series at The Wick in Southwick, Massachusetts. The typical two-stroke air-cooled, twin-shock rear suspension machines gave way to machines that were water-cooled and fitted with single-shock absorber rear suspension. The United States, Belgium and Great Britain have had the greatest success. Rider participates motocross championship.