It was never a pretty bike, but looks are not everything. And judging by the sheer number of these bikes sold, the Yamaha XS650 was a great success.
What made this bike special for many was the reliable parallel 4-stroke twin-cylinder engines. This engine has been used in everything from world championship sidecar MX bikes, to helicopters!
Originally developed in collaboration with Toyota cars, the Yamaha engine was unique in one critical area, its bearings. No doubt based on their 2-stroke experience, Yamaha used needle bearings for the big end bearings, and ball bearings for the crank--even the camshaft of the OHC engine was supported in ball bearings.
Today, the Yamaha has a large following in the classic community, and with around 500,000 units produced between 1969 and 1985, there are plenty of examples to choose from. Also attracting classic buyers is the spares' availability for this bike which is plentiful.