The Yamaha SR 400 was a standard motorcycle manufactured by Yamaha from 1978 to 2012. The bike was powered by a single-cylinder engine and was a street version of the Yamaha XT500 model, with a standard riding position and styling resembling the UJM of the 1970s.
The bike was manufactured alongside the SR 500 model and produced until 1999. Both machines were identical, the only difference being the larger engine of the SR 500 model. The more significant displacement was achieved with a different crankshaft and a shorter piston stroke.
The SR 400 machine was marketed in the Japanese Domestic Market (JDM) from 1978 to 1981, and in the European, American, and Oceanian markets, the model was introduced in 2014.
The 1978 Yamaha SR 400 motorcycle came equipped with standard features, such as a steel front fender, a one-piece dual seat, a teardrop-shaped fuel tank, a chromed exhaust system, a round headlight, and lightweight wire-spoke wheels.
The bike was built on a double cradle steel frame with a 35 mm telescopic fork on the front with 150 mm wheel travel and five-way spring preload-adjustable side-mounted shock absorbers on the rear with 105 mm wheel travel.
In the performance department, the 1980 Yamaha SR 400 packed a 399cc four-stroke single-cylinder air-cooled engine fed by a VM32 carburetor, delivering 23 hp with a peak at 6,500 rpm and 27 Nm (20 lb-ft) torque at 3,000 rpm.