Abstract
A study of the lateral motion of motorcycles has been conducted through experiments on four large motorcycles of Japanese manufacture. A total of five experimental procedures were applied to straight or nearly straight running conditions and curve running conditions, and the results of each experiment were arranged by frequency response function in terms of input and output. Consideration is given to steer torque and rider lean angle as independent control inputs, and both single-input and dual-input analysis were conducted. This analysis revealed that the major determining input force is steer torque, and that the rider lean angle by itself has almost no influence on output.