Vibrations, both mechanical and acoustic, mainly affect ride comfort, exposing driver to persistent disturbs. Ride comfort represents one of the most important dynamic performances of motorcycles. Mechanical vibrations are mainly caused by volumetric engine inertial unbalances and irregularity of the road profile. Shaking forces caused by engine unbalances are probably the most critical input, also considering the reduced efficacy of engine mounts as suspension/filter. The main aim of this work is to provide a methodology to clearly identify structural properties involved in the propagation...