The GT125 and GT250 Comet are versatile sportbike and naked sportbike models known for their V-twin engine configurations and competitive positioning in the entry-level to mid-range motorcycle market. These models, originating from South Korea, offer a blend of performance and accessibility for riders. Typically featuring liquid-cooled engines with displacements around 124cc for the GT125 and 249cc for the GT250, and a chain drive final drive, they are designed for a range of riding experiences. Their engineering quality and reliability are supported by a focus on providing accessible performance, making them a popular choice for riders seeking value and an engaging riding experience. This Workshop Service & Repair Manual in English provides comprehensive guidance for the maintenance and repair of the GT125 and GT250 Comet. It covers all essential vehicle systems, including the engine, gearbox, clutch, cooling system, fuel system, braking system, suspension, electrical system, bodywork, and exhaust. The manual offers detailed, step-by-step instructions for routine maintenance, diagnostic procedures, and complete repair of components, suitable for both owners and professional technicians. Its purpose is to empower users with the knowledge to effectively service and maintain their motorcycles, ensuring optimal performance and longevity.