Unveiled in 1977 as the successor to the Z1 900, it differed from its forerunner with a 4 mm increase in cylinder bore, which brought the displacement up to 1,015 cc. Another technical improvement concerned the addition of a modern disc brake to replace the drum brake. During its years of production, as well as a general increase in the power generated by the engine, developments focused on the bike's looks. It was, indeed, offered in a more sporty and aerodynamic version, fitted with a small cowl on the front headlight.