This document serves as a comprehensive workshop service repair manual for the T4 350 and T4 500 dual-sport/adventure motorcycles, produced from 1987 onwards. These versatile Italian-engineered machines, often featuring robust Rotax engines, were designed for both on-road versatility and off-road capability. This manual provides detailed information essential for understanding, maintaining, and repairing these iconic motorcycles, ensuring their continued performance and reliability. The scope of this manual encompasses all critical aspects of the T4 series, including detailed procedures for engine rebuilding, powertrain systems, chassis and suspension components, and electrical systems. It offers step-by-step instructions, troubleshooting guides, and technical specifications, along with crucial safety guidelines. Whether you are a dedicated owner or a professional technician, this resource is designed to facilitate efficient and accurate maintenance and repair, covering everything from routine servicing to in-depth diagnostics and component overhauls.