Ducati has arrived on the SMX circuit to great fanfare. The Italy-based manufacturer, better known for road racing, is the latest in a long line of brands to enter the AMA space of Monster Energy Supercross and Pro Motocross, following Beta and Triumph. Currently, there are 10 different motorcycle makers participating in SMX, though that number could change, as nothing is guaranteed in motorsports. With that in mind, we thought we’d look at some brands that have already come and gone from this highly competitive racing ecosystem.