The horsepower of a 250cc engine varies greatly, depending on a number of factors. The average horsepower for a 250cc in a dirt bike is between 20 and 30. A Briggs & Stratton snow blower using the same style of engine has only 8.5 horsepower.
The maximum horsepower for the 250cc reported in a 2012 study of dirt bikes by "Motocross Action Magazine" was 49.77. However, the numbers varied greatly, depending on the make of the bike and the RPM. The KTM 250SX engine registered the highest horsepower at 7,000 through 10,000 RPM, averaging between 39.43 and 48.63. The Kawasaki KX250F averaged 39.27 horsepower at 12,000 RPM.