308 Throttle cables/linkage by carbs - fine tuning? | FerrariChat
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308 Throttle cables/linkage by carbs - fine tuning?

Discussion in 'Technical Q&A' started by Mike328, Feb 6, 2004.

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  1. Mike328

    Mike328 F1 Rookie

    Oct 19, 2002
    2,655
    Boulder, CO
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    Mike
    #1 Mike328, Feb 6, 2004
    So I'm trying to get the throttle/carb linkage by the carbs adjusted PERFECTLY so that opening of the throttle is done exactly in sync.

    What I find is, although I can get very close, I can never get it *exact*. Barely pulling on the throttle cable will invariably JUST begin to open one bank before the other.

    As it turns out, my thinking is the finest you can adjust these is within a distance "d" which is the difference in position of the rotatable throttle lever "grip" between one complete revolution around the throttle shaft threads.

    Is this as good as I'm going to get it? I mean, I had it pretty darn close before, but I could still engage one bank before the other with just the smallest amount of gas.

    --Mike
     
  2. yelcab

    yelcab F1 World Champ
    Consultant

    Nov 29, 2001
    13,261
    San Carlos, CA
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    Mitchell Le
    #2 yelcab, Feb 6, 2004
    Mike

    Compared to world peace, this is a pretty small problem. Good luck making it perfect. I gave up weeks into the process.
     
    Dane likes this.
  3. Mike328

    Mike328 F1 Rookie

    Oct 19, 2002
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    Mike
    #3 Mike328, Feb 6, 2004
    LOL. I was beginning to suspect as much--"pretty good" is as good as it may get.

    It seems then that you never got it perfect?
     
  4. bill308

    bill308 Formula 3
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    May 13, 2001
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    Bill Sebestyen
    #4 bill308, Feb 7, 2004
    Mike,

    I'm not sure I understand your description for adjusting the bank to bank synchronization. Are you trying to adjust just one end of the linkage rod?

    Although tricky and time consuming, I release the lock nuts on both ends of the linkage rod, twist the rod an appropriate amount, then tighten the lock nuts. Each rod is threaded for a right hand thread on one end and a left hand thread on the other, like a turn buckle. In theory, this provides infinitly fine adjustment, but because of sloppiness in the threads, tightening of the lock nuts has some effect on the net adjustment.
     
  5. 4re gt4

    4re gt4 Formula 3

    Apr 23, 2002
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    Hans E. Hansen
    #5 4re gt4, Feb 9, 2004
    Mike: I'm with bill308 on this one. The adjustment should be infinitely fine via the linkage rods, and their respective lock nuts. You can't help but have a bit of slack in the ball joints at the rod ends, but you should be able to get simultaneous opening, with enough fiddling. Mine works fine, at least as well as my old eyes are able to discern.
     
  6. Mike328

    Mike328 F1 Rookie

    Oct 19, 2002
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    #6 Mike328, Feb 9, 2004
    Fantastic! Thanks, guys!

    The revelation is that the "delta d" minimum adjustment distance that I'm talking about, by rotating the actual knobs on the linkage, is not the way I need to be doing things.

    I just now realized that with the threading, turn-buckle style on the linkage rod, I need to be actually ROTATING the linkage rod and NOT the little knubs at the END of each rod (which accomodates the ball on the carb throttle level plate). Doing so will actually COMPRESS and EXPAND the distance...

    Just goes to show how much I have to learn. Linkage rods ain't software.

    Thanks for your help--I now know how to get the carbs linkage adjusted to the precise level that I want.

    --Miek
     

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  7. 4re gt4

    4re gt4 Formula 3

    Apr 23, 2002
    2,279
    Roseburg, OR
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    Hans E. Hansen
    #7 4re gt4, Feb 10, 2004
    Mike: The little "knobs", as you call them, should be adjusted as tight as possible w/o causing any binding. Throw a dab of grease in there as well.
     

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