This manual covers the LT-A400 and LT-A400F QuadRunner/KingQuad All-Terrain Vehicles produced from 2007 to 2009. These robust ATVs are designed for a wide range of utility tasks and recreational riding, offering a blend of dependable performance and enduring engineering. Known for their reliable 4-stroke, single-cylinder engines and versatile automatic transmissions, these models provide a comfortable and capable experience across various terrains, embodying a legacy of producing durable and user-friendly off-road vehicles. This comprehensive workshop repair service manual provides detailed guidance for owners, mechanics, and technicians. It covers all aspects of maintenance, troubleshooting, and repair for the specified LT-A400/LT-A400F models, including engine mechanicals, fuel and cooling systems, drivetrain, suspension, brakes, steering, and the electrical system. With step-by-step instructions, diagrams, and diagnostic charts, this manual is an essential resource for keeping your ATV in optimal condition and ensuring its longevity and performance.