Honda Carburetors
Honda applications use a two or three barrel "down draft" style carburetor.
 
Some early Civics (1973-1976) used a Hitachi 2 barrel; however, after 1976 Keihin became the standard carburetor for all American Honda automobiles.

The Keihin 3 barrel carburetor was used widely from 1975 to 1987. In this design, the third (auxiliary) barrel operates as an extension to the primary barrel.  The auxiliary barrel delivers a small but rich fuel mixture to the engine. The primary barrel delivers a large overall volume (however lean) fuel mixture.