This manual covers the models produced between 1979 and 1986. These motorcycles, including variants such as the LTD, Spectro, CSR, GP, and Shaft models, were known for their inline-twin, four-stroke, air-cooled engines, offering a balance of performance and reliability for their era. The engineering quality of these bikes, with displacements around 498cc for the KZ500 and 552cc for the KZ550/ZX550, positioned them as competitive options in the mid-size sport and standard motorcycle segment. The legacy in performance motorcycle development is evident in the progression from the KZ500 to the more advanced KZ550 and ZX550 series. This comprehensive service and repair workshop manual provides detailed instructions for all aspects of maintenance and repair for these models. It covers engine systems, drivetrain and transmission, chassis and suspension, braking systems, and the electrical system, including troubleshooting guides for common issues like carburetor wear and electrical faults. The manual is designed for enthusiast owners, independent repair shops, and restorers, offering extensive procedures for periodic checks, adjustments, fluid changes, component replacement, and in-depth diagnostics. Its professional quality ensures users can effectively maintain and repair their vehicles, offering significant value and cost savings.