This recommended practice establishes a method for measuring total motorcycle sound pressure levels under full throttle acceleration and closed throtle deceleration. Factors which contribute to total motorcycle sound include those from the exhaust, intake, mechanical components, tires/road interface and others. SAE J47 is recommended for measuring the maximum total motoreycle sound pressure level under wide open throtle acceleration and closed throte deceleration.SAE J47 is intended to capture the maximum total sound pressure of a motorcycle but is nat intended to reflect real in use operating conditions. SAE J331 is intended to capture the sound pressure emitted during a typical in-use acceleration or deceleration of a motorcycle. Two other standards address measurement of exhaust sound pressure levels of stationary motorcycles; SAE J1287 is recommended for off-highway motorcycles, and SAE J2825 is recommended for on-highway motorcycles.
