23 Jul Ducati increases engine displacement Posted at 11:38h in 1991, Hall of Fame by Riccardo Share 1991 Doug Polen – Ducati 888 – Superbike After Fred Merkel, Doug Polen brings the Superbike title back to the U.S. on a Ducati with the engine cubage increased from 851 to 888 cc. Tags: 1991, Doug Polen, Ducati, Superbike