XS400

Introduced for the 1977 model year as an enlarged successor to the earlier 360cc twin, this middleweight four-stroke was aimed at riders wanting an accessible, practical road bike rather than a flagship performance machine. Early versions used a simple air-cooled parallel-twin layout and were offered in several trims, including sportier and more commuter-oriented variants. Over the years the nameplate evolved with restyling and mechanical updates, and later versions moved into the DOHC era in some markets, reflecting Yamaha’s effort to keep the platform competitive through the 1980s. The family became known as a dependable, approachable middleweight with broad international availability, and it remained in production in various forms until 1990.