James Dean designed the JDJetting kits so that you don't have to be an expert to get professional high performance results!! The James Dean custom jetting kit is designed to improve throttle response throughout the range by using specially made multi-taper needles. Exceeds the performance of other standard factory needle options and technical support is provided. Low and High altitude custom designed triple taper needles Extra genuine Keihin main jets and needle clip included Accelerator pump modification to improve throttle response Dyno Tested and Developed with settings from sea level to 12000ft elevation You cant buy this level of performance from the factory manufacturer or other aftermarket suppliers