What is the fastest 4 stroke 125cc dirt bike?
The fastest 4 stroke 125cc dirt bike is the KTM 125 SX. It has a top speed of 65 mph and can reach 0-60 mph in 3.5 seconds. It has a liquid-cooled, single-cylinder engine that produces 15 horsepower and 11 lb-ft of torque. It also has a six-speed transmission and weighs 215 pounds.