This manual covers the Z250 and KZ305 models produced between 1979 and 1982. These motorcycles are characterized by their air-cooled, 4-stroke, DOHC parallel-twin engines, with displacements of 238 cc for the Z250 and 302 cc for the KZ305, typically producing between 20-35 horsepower. Featuring a 6-speed transmission and chain drive, these bikes offered a balance of performance and practicality in the naked bike segment of their era. A Japanese corporation with a strong heritage in motorcycle engineering, built these models to be reliable and responsive. This comprehensive repair and workshop manual provides detailed information for owners and technicians. It covers a wide range of systems including general information, routine maintenance, engine removal and installation, fuel and lubrication systems, transmission, steering, shocks, bodywork, intake and exhaust, and the electrical system. The manual includes procedures for repair, maintenance, troubleshooting, diagnostics, component installation and removal, adjustments, and overhauls, designed for both novice and experienced mechanics. It serves as an essential resource for maintaining and repairing these classic motorcycles.