The Panigale V4 R is equipped with a 998 cc (1-liter) V4 engine that produces a maximum power output of 221 horsepower (164 kW) at 15,250 rpm. This results in an impressive power output of 221 horsepower per liter of displacement.
It's important to note that motorcycle technology is continuously evolving, and new models are regularly introduced with higher power outputs. Therefore, there may be newer motorcycles with even higher power-to-displacement ratios available since my last knowledge update. It's recommended to consult the latest information or contact the respective motorcycle manufacturers to obtain the most up-to-date figures.