A new Yost Power tube specifically designed for the stock H-D CV-40 type carburetors (1988-later). After intense research and development, Yost has developed a Power tube that is not only very easy to install, but it also transforms the stock CV-40 type carburetor into a very competitive high performance carburetor (equal or better than many other high performance carburetors and costing much less than the competiiton). Fits Both Big Twin and Sportster. Sold as a kit. For 1988-later CV-40 Keihin carb.