It would be some time before a bike resembling a pit bike as we know it would be released. An important milestone in motorcycle history, the Honda Super Cub 50 began the revolutionary rise in popularity of the Japanese motorcycle, with production reaching millions of units - the Honda became incredibly popular in the United States. Despite not being a pit bike by any means, the Honda did lay further ground work for mini bikes to come, being designed around the same 4-stroke engine many use today.
Arguably the bike that started the revolution - the four-stroke engined Honda Z50 Mini Trail (AKA the 'Monkey Bike'). In addition to being the first Honda bike made to be used off-road, this bike had many design features which led to it's popularity in the US and around the world. It could be stored easily in a truck or trailer for easy transportation, and throughout the Z series life saw many design updates and improvements. Pit bike parts for this bike and other models were freely and cheaply available, making them an ideal run-around.
Modern bikes have not strayed far away from early designs, with major differences being longer wheelbases, suspension and taller handlebars as well as improved breaking systems. These changes have allowed adults to comfortably and safely ride and also increase the durability of what these bikes can tolerate.
So there you have it, a quick recap of where today's modern pit and mini moto bikes have developed from. Hopefully you've learned something! ;-)