1983 Dual Carb Setup

Discussion in 'General Motoring' started by DTI TECH, Oct 23, 2004.


    DTI TECH Guest

    Hi folks, I have an '83 Honda Prelude with a Motor from an 89 prelude. My
    car didn't have the chip for fuel injection so I had to put the dual carbs
    on the motor. I'm just having one hell of a time seting up the carbs so
    it'll run correctly. Anywhere I might find help to do this? Most mechanics
    say I need some kinda unisen(sin) thing to set'em up, is this true?

    Any help would be appreciated, thanks!

    DTI TECH, Oct 23, 2004

    J. Guest

    The '84 Lude manual shows a carb synchronizer and adapters (in place of the
    carb screens and air intake flanges) to measure the air flow through both
    adapters. This is done prior to adjusting idle speed, mixture adjustment
    (via propane enrichment method), fast idle, and carb float level
    adjustments. If air flow is different:
    1. loosen the carb adjusting screw locknut and adjust screw.
    2. the screw only affects the right carb; turning the screw clockwise
    decreases air flow, ccw increases airflow.
    3. if flow rates can't be balanced, check for air leaks or carbon build up
    on a throttle valve.
    4. retighten adjusting screw locknut.

    I always heard the dual carbs were a pain if they needed work. Never had
    any fuel problems with my 84 before selling it for a 90 lude. If the 83 and
    84 emission controls were the same, you must have eliminated half the vacuum
    hoses during that swap. I had never seen so many hoses before or since!

    Under what conditions do you have problems? (idle, power, cold, hot)

    J., Oct 24, 2004

    jim beam Guest

    are they new carbs? if so, just use a flow meter to balance them.

    if they're old, i recommend you completely strip and recondition with a
    kit you can easily buy. trying to balance bad carbs is an exercise in

    you can make a rough [uncalibrated] flow meter from an old clear
    ballpoint pen whose outer has a tapered center. drop a small glass bead
    [needs to be reasonably heavy] in there, one whose size makes it nice &
    loose at the top, but snug at the bottom. then attach a rubber hose to
    the top, the wide end, and gradually place the other over the carb
    idling air circuit inlet. keeping the pen vertical, the ball should
    rise as the flow of air in the tube suspends it. "gradual" is very
    important. if air gets sucked too quick, the momentum of the ball can
    eject it from the tube and even drop it into the carb. you could try
    preventing this by gating the top of the tube with a wire so the air can
    pass, but not the ball. mark off the level the ball rises to, then
    repeat for the other carb. adjust until both carbs are sucking the same
    amount of air, as indicated by the ball rising the same amount. using
    this method, you can easily balance 4 or more carbs without problems.
    jim beam, Oct 25, 2004

    Eric Guest

    Didn't the '83 Lude have a triple carb setup with a small carb in the middle
    of the other two for the CVCC valves? The Preludes lost their CVCC valves
    in '84 and had a true "dual" carb setup. In addition to the comments from
    the other posters, the presence of the auxiliary carburetor may be a
    contributing factor to your problem.

    Eric, Oct 25, 2004
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