scottyd, exactly, that's what I was trying to say, the flapper door is opened by the sucking of the engine thru it, if u held a qjet in ur hand and opened the throttle the flapper will not open unless you move the stopper arm on the passenger side of the carb,the secondaries kinda bind like they are stuck, the door opening speed is the wound up spring, a loose wind and and the door flaps open and you get a bog, tighten the spring and vacuum draws the door slowly open allowing the engine to digest the heavier load, right by that spring the is a tang the restricts how much the door opens at all, some are bent some are shaved for more travel, and others have drilled and set screw in the base for adjustment,,the more the door opens the bigger the carb,, the secondary rods always move regardless of the flapper speed and travel they are on a cam that rotates them out of their orifices, there are a massive selection of rod sizes to match carb needs,,
