The CVCC engine requires a small amount of rich mixture for the auxiliary combustion chamber and a greater amount of lean mixture proportioned to the load for the main combustion chamber, with the overall air-fuel ratio which has to be properly controlled. In order to fulfill the above requirements, the carburetor has to provide both the main and auxiliary fuel system independently and connect their throttle valve shafts with each other by a link mechanism.
Besides this, the carburetor is confronted by the problems that are introduced by the leaner mixture, i.e., idle stability, surging, transient performance, cornering problems, and starting performance. It is also required to be equipped with exhaust emission control devices so as to meet stringent official regulations.
It is not too much to say, indeed, that the development of the carburetor was the key to the success of the CVCC engine.