Motorcycle Noise Test Procedure Evaluation: SAE XJ331a and XJ47

SAE Recommended Practice XJ331a, Sound Levels for Motorcycles, was developed to represent vehicle operation and is well suited for determining noise levels of new motorcycles offered for sale. Similar procedures have been used for this purpose since 1969. SAE Recommended Practice XJ47, Maximum Sound Level Potential for Motorcycles, was developed as a manufacturing tool to determine a vehicle's maximum sound level potential and is an excellent tool for manufacturers. Because of its severe operating requirements, SAE XJ47 is not suited or recommended to be used as an enforcement standard.