the carter RBS is a one-barrel downdraught carburetor with a one-piece cast aluminum carb body, natural stamped steel fuel bowl, venturi machined into carb throat, commonly 215 cfm for the ford 250 six.
hot air choke "carter climatic control", zamac choke housing staked to carb body. hardware, rods, levers cad plated or zinc dichromate finish.
basic functions:
idle system meters fuel at idle through the main jet and into the well tube and air bleed where it is mixed with air; emulsified air/fuel is drawn to the dogleg booster then.
additionally, off-idle fuel enrichment is metered by a vacuum-controlled step-up rod which allows more fuel to the well tube through a second, non-removable jet.
internal accelerator pump is operated by adjustable rod and lever.
the carter RBS basically is a 1V-version of its bigger brethren, the AFB, and also shares some similarities to the BBS 2bbl.
Unlike the AFB and edelbrock clones, it was designed for function on its given application, not tunability.
No knowledge about different jet sizes, but after reading some books by Vizard and Holley it seems pretty obvious that the stock main jet is too small. I first tried to adapt a #80 holley jet, but ended up fabricating my own jet (.079"). currently converting a RBS throttle to needle bearings, knife edged-plate, custom stainless shaft and seal.
