This type of racing is still going on. Google "AMA flat track racing" to find where and when you can see it. You can also view it on the YouTube. It's one of the few forms of motorcycle racing where the winner isn't always predictable. The bikes race on 1/2 to 1 mile ovals, there's only a rear brake and it's use is only to slow in case of a downed rider or at the end of the race. Straightaway speeds of 120 mph are common, and they slide around the corners at 100+.

Full speed ahead, and no brakes on those bikes. What could go wrong?

Early dirt racing bikes were primitive even for the time, according to my late father who raced a few: most notably, they had no brakes -- an ignition cut-off served to slow down a little, often with a string connecting the cut-off to the rider in case he fell off, as a kind of "dead man" switch.

Most also had but one gear and they were push-started with the aid of whatever crew the rider could muster, thereby saving the weight of a recoil starter. And on short tracks, typical of county fairs, the most valuable driving technique involved the infamous "pendulum skid," with riders taking the curves much as automobile drifters do today (but with two wheels fewer, to add to the excitement).

How those fence rails ended up in the grass.

Six weeks after the sinking of the Titanic.

My grandfather was a bike racer. He rode in what we called a "motorcycle scramble" on a dirt track very similar to this one.

I remember watching him work on his bike when I was very young (50-plus years ago now).

Although I never was allowed to go watch him, I was told he was quite good.