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. Key Features 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 main jets made by Keihin and needle clip included Accelerator pump orings for better off idle responseIncludes main jets, custom multi-taper needles and needle clip.