Yamaha SR500 is a very popular single cylinder motorcycle. Yamaha put the bikes on sale in 1978 as a road going version of XT500. Sold pretty good in the US, Europe and Australia. SR500 was discontinued but SR400 was kept manufactured in Japan where its popularity never declined till 2008 when stricter emission standard of Japan killed the production.
However, Yamaha is reintroducing SR400 with fuel injection, replacing old-fashion carburetor.
The SR400 is essentially the same bike as the SR500, but with a shorter stroke and heavier muffler to pass tighter emission restrictions.
The SR500 was well received on conception, largely due to its contemporary styling and reliable Yamaha single cylinder 500cc powerplant. The chassis and engine has served as a popular basis for many cafe racers, street trackers'and bobbers. There are many bike shops that are specialized in customizing SR series.