This project developed the specifications for a motorcycle dynamometer and motorcycle cooling system to be used in motorcycle exhaust emission certification programs. In the development of dynamometer specifications, various power absorbers, roll assemblies, and inertia assemblies were evaluated and their performance related to road data. Variable-flow blower systems were examined as a technique to simulate on-road engine cooling. Specific cooling system parameters studied included blower style, ducting requirements, noise levels, efficiency, power requirements, flow control methods, cost, and delivery. This volume, the specifications, define and establish the required configuration, performance, and design characteristics of a motorcycle dynamometer and cooling system to be used by the U.S. Environmental Protection Agency for the purpose of conducting exhaust emissions certification tests and fuel economy measurements.