The Thunderlide CV carburetor new calibration set for the Harley Davidson XL1200S, built in 1998 to 2003, offers a comprehensive solution to optimize engine power. The set contains an innovative, lightweight slide that improves the reaction time of the engine to gas commands and helps to reduce fuel consumption. Various main nozzles, a equal pressure membrane, a needle, a injection nozzle, a accelerator pump ball, a mixed pipe and required drills for adjustments are included. In addition, security clips and a assembly kit are added. Detailed instructions for the installation and setting of the kit are also provided.