The 1925 Harley-Davidson JD motorcycle introduced Harley's familiar tear-drop-shaped fuel tank. Sidecars were popular accessories of the day as these vehicles often served as a family's primary form of motorized transportation. Read about the Harley JD.
The 1973 Kawasaki Z-1 motorcycle was Kawasaki's answer to Honda's popular models of the late 1960s. It had a 903-cc double-overhead-cam inline four that became the benchmark other companies tried to beat. See pictures and learn about the Kawasaki Z-1.