What pipes are there on the throttle of the old Excelle?

Exhaust pipe and intake manifold. There are only two pipes and an exhaust pipe on the throttle of the old Excelle, which makes the exhaust gas reflux reach a certain emission standard; One is connected to the intake manifold and distributes the combustible mixture provided by the carburetor to each cylinder. The side of the throttle near the combustion chamber is generally dirty, with traces of black carbon deposition and needs to be cleaned.