Who invented flat track motorcycle racing?

Answer 1

It didn't take long after the invention of the bicycle for people to begin racing them. An soon after that, people started modifying the bikes to become better racing material. So there's no single inventot of the racing bike.

Answer 2

The Australians invented the broadsliding style of racing, on 'borrowed' dirt horse tracks, where the rear wheel is allowed to slide out on corners - this makes for spectacular viewing, as the riders struggle to control the machines solely by use of throttle and lean angle, as the rear wheel kicks up a rooster tail of dirt.