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Colortune to Borrow

Discussion in 'Hangout Lounge' started by Antothoro, Sep 21, 2021.

  1. Antothoro

    Antothoro Member

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    I'm in the North Texas (DFW) area and looking for a Colortune to borrow (or buy). Anybody out there got one?
     
  2. tabaka45

    tabaka45 Well-Known Member

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    You can set your pilot screws without one, but it takes time. The "normal" setting is 2 1/2 turns open, but that was very rich for my XJ700. Try the following method that I came up with. Close the pilot screws to about 1 1/2 open. Put in brand new plugs. Ride about 15 -20 miles. Pull the plugs and look at them. If the porcelain tip is all white, and it probably will be, open the pilot screw about the width of a dime. Continue this ride and read process until each plug has a nice light gray or light tan color which is what you are looking for. Each plug setting will probably be a little different because of different carbs, cylinder compression, etc. Mine took 5-6 rides over a couple of weeks and my pilot screws are open anywhere from about 1 3/4 to a little over 2. By the way, I have a colortune plug and just used it to find the starting point, that being where the flickers of white (lean indicator) flame started to show.
     
  3. Minimutly

    Minimutly Well-Known Member

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    Here’s a quicker way to do it - but you need to “tune your ears in” to the engine note and speed.
    Start at 2 1/2 turns out. take the bike for a long gentle ride, get it nicely heat soaked. Put it on centre stand, note the rpm, but listen to it as well. Starting from one end, turn the mixture screw in, slowly, no more than a quarter turn at a time. Listen, has the rpm dropped? No? Then carry on, slowly until it does. When your sure you detect a drop in rpm, go back the other way, counting turns as you go. When it speeds back up, note how many turns. Carry on until it starts to slow again. Then, remembering how many turns out you are from “weakest point”, divide by two to get back to the middle. You should be correct to within 1/2 a turn or better.
    Do this for all four pots. A fan is good to blow air across the engine, but once you’re practiced you won’t need one.
    Then repeat, just to be sure. It doesn’t take long to tune into it, and practice makes perfect.
    If the engine misses a beat now and again you are weak on one or more pots. If it has a rhythmic beat you are rich.
    Plug cuts are fine, but they tell you little or nothing about idle mixture, unless it’s rich as hell on idle and you didn’t cut it before idling.
     
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  4. XJ550H

    XJ550H Well-Known Member Premium Member

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    if you buy one from xj4ever it will be there very quickly
     
  5. Minimutly

    Minimutly Well-Known Member

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    I wrote (typed) this from my head, and omitted to include that as you get closer to the right mixture, you will need to adjust the idle speed down, and, more of a fiddle, perform a full synch or two, so you need the kit to do this.
     
  6. Antothoro

    Antothoro Member

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    Thanks for sharing these procedures guys. I'll need to re-read it a few times and write it down in a way that I follow it step by step.
     

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