In 1996 he rode for the Aprilia factory in the 500cc class aboard a bike with a V-twin, 250cc engine that had been enlarged to 380cc.

Aprilia tried to take advantage of the bike's lightweight and agility against their more powerful competition.

Romboni managed to finish in 10th place in the 1997 season before Aprilia withdrew the project.

At Monza he briefly ran third behind Carl Fogarty and Troy Corser before he collided with Aaron Slight and hurt his leg.

On 30 November 2013, Romboni died in a crash during the second edition of the Sic Supermoto Day, a race in honor of the memory of fellow Italian Marco Simoncelli, who also died in a crash in 2011.