|If you have never heard of, or seen a ysr50 before here you go. These little bikes are so adicting. I first saw one of these at a local Honda dealership here in Sacramento when I was buying my first dirt bike and wanted one ever since.
These bikes are about half the size of a full size sport bike. They aren't made anymore they were in production from 1986-92, but are probably more popular now than when they were new. There are race venues for ysr's everywhere, with many different classes. Ysr racing is probably the cheapest way to get into racing bikes.
Not so many people ride them on the street anymore just because you have to be sick in the head (like me) to do so. Like I said they are 50cc's and don't have the highest of top speed stock (somewhere around 50 +/-) or guts to get there. Although there was a Canadian model made with a 80cc engine that I am sure helped out alot.
These bikes have also fallen victim to the bigger is better mentality. Many people,including myself, have done engine swaps into the ysr with all kinds of engines. Check out
my Engine Swaps to see what you will need and what engines I have found that work. My engine swap was a AT175 enduro bike.