The KTM 990 Adventure, also known by its model code LC8 Adventure, represents the first generation of KTM's formidable adventure touring motorcycles, produced from 2003 to 2007. Building on KTM's rich Austrian heritage in off-road racing, this model is engineered for versatility, excelling in long-distance touring and challenging off-road exploration. Its design philosophy prioritizes a lightweight, agile platform, powered by a potent 999 cc V-twin LC8 engine renowned for its substantial torque and high-revving performance. The 990 Adventure is celebrated for its robust construction, capable handling, and a strong reputation for conquering diverse terrains, making it a highly regarded choice for dual-sport riders seeking adventure. This comprehensive service and repair manual provides detailed guidance for the KTM 990 Adventure, covering the production years 2003 through 2007 for the Standard model variant. The manual offers in-depth information on all major vehicle systems, including the LC8 engine, fuel system, cooling, electrical components, and chassis. It outlines procedures for routine maintenance, such as oil changes and filter replacements, as well as more complex repairs like engine overhauls and suspension servicing. Essential technical specifications, diagnostic procedures, and troubleshooting guides are included to assist owners, mechanics, and technicians in maintaining optimal performance, ensuring reliability, and effectively addressing any issues that may arise.