What did the first dirt bike made look like?

No one person invented the dirt bike. People began to modify their bikes to ride in the dirt, starting with knobby tires and better suspensions, changing gearing/sprockets, frames, doing everything posssible to lighten and strengthen them, getting rid of parts not needed in dirt riding (lites, horn, etc.).

The first motorcycle designed specifically for offroad use may have been by Sigfried Bettmann of Coventry, England, for Triumph Motorcycles in the year 1914