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Gunson Colortune

Discussion in 'XJ Technical Chat' started by dowski68, Jun 2, 2017.

  1. waldreps

    waldreps Active Member

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    All the jets are totally stock per specs and in the correct location per the images posted on here and not from the manual. Exhaust, airbox, filter, etc are all stock. Valves done about 1000 miles ago if I remember correctly without checking my notes. New plugs after doing the carbs. All the throttle seals have been replaced as have everything that came in the deluxe rebuild kit from Len. Wet set done and checked several times. I'm confident that everything is done right with the carbs according to the Church of clean except the mixture settings since the colortune didn't want to cooperate like I think it should. I haven't had time this year yet to fiddle with them or check the plugs as I've only gone on 3 short rides.
     
  2. tabaka45

    tabaka45 Well-Known Member

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    Get the engine warm. Install the colortune plug. Close the pilot screw until you get a white flame--on my xj700 that less than 1 1/2 open. Open the pilot screw until the white disappears. Repeat for all cylinders. Put away the colortune since you no longer need it. Install new plugs and ride 15-20 miles and look at the plugs. You are looking for a light tan color. If the plugs are still white open the pilot screw about the width of a dime. Take another ride and look at the plugs and continue to do this adjusting the pilot screw no more than the width of a dime until you get light tan color on the plugs. I did this over a couple of weeks. My pilot screws are set between 1 3/4 & 2 1/4. Be sure to start with new plugs in order to be able to see the color change.

    If you can't get a white flame you should determine why that cylinder is overly rich before going further. If you have to open the pilots more than 2 1/2 to get rid of the white flame, you need to determine why that cylinder is getting too much air before proceeding.
     
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  3. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    The only thing that the Colortune does is let you see what's happening inside of the combustion chamber. There is nothing about it that can be inaccurate.
    Are you waiting a few seconds after each bump of the idle screw before checking the color?
     
  4. waldreps

    waldreps Active Member

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    Yep, I'm following the instructions with the Colortune exactly but I never get a white flame. I get no flame to light blue flame then finally changes to orange flame. I realize it's not the Colortune itself that's inaccurate just how the process seems to work for me. I've tried waiting between my mixture screw adjustment and that hasn't seemed to make a difference. Again, it could be my eyes not being able to differentiate between white and light blue flame. I don't know...I just thought using the Colortune should be easy and get me to within a few dime widths of ideal but it only seems to get me within 2 full turns which doesn't seem to even be in the ballpark. I know other people love it and it works great for them so it's probably just me. I think I'm doing it right but I must be screwing up or not able to see the color changes or something...no big deal. I'll probably just end up setting them to the default starting point for my bike of 2.5 turns out and adjust from there by reading the plugs. Thanks for the suggestions...I appreciate it and I didn't mean to hijack this thread. Sorry.
     
  5. tabaka45

    tabaka45 Well-Known Member

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    If you do it in the dark it should be easy to see the white. If you are not going to use it then I would start with new plugs and the pilots open no more than 1 3/4. Then ride and read the plugs and adjut as needed.
     
  6. waldreps

    waldreps Active Member

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    tabaka45, I've always done it in a dark garage and it still always looks light blue to me until it finally turns orange :(. Thanks for the advice about starting at a low number of turns. That makes sense so the new plugs don't get too dark right away. Better to slowly creep up on perfect instead of going past it.
     
  7. XJ550H

    XJ550H Well-Known Member Premium Member

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  8. waldreps

    waldreps Active Member

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    Got both of those....tried the halfway between here and there thing as the instructions said and also the way others have suggested. It's so hard to tell when the color changes and the yellow or orange totally disappears that it seems like just guessing to me. I'm a perfectionist so I've tried really hard to follow what everyone says to the T but it just doesn't seem to work good for me. Like I said, I'm sure it's just me since others have had success with it. I do appreciate the suggestions though.
     
  9. Stumplifter

    Stumplifter Well-Known Member

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    Have you tried having someone else look?
    My eyes are getting old and sometimes . . . .
     
  10. waldreps

    waldreps Active Member

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    No, I haven't...don't really have anybody else that would want to help with motorcycle maintenance. I'm sure my fiancee wouldn't want to try.
     
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  11. dowski68

    dowski68 Well-Known Member

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    Ah another beautiful day for a ride to work. If I go through down town it takes like 15-20 minutes to get there. What I don't really care for is the stop and go, I believe there are only 22 stop lights LOL Only.
    So to curtail the abuse to my bike I have been taking the alternative routes which skirt the outside of town. This provides more riding less stopping- enhanced by the beauty of nature.

    As with any engine stop and go wears an engine down quicker, compared to lets say freeway miles or country back roads.


    Regarding air fuel mixture-

    Going to buy a temp gun and check this theory out after work.

    I recently watched a video from an enthusiast of motorcycles in general no real Preferences other then 70's-80's bike.
    Dawino on YouTube. Located in Florida
    He stated that he uses a temperature gun and bases his air fuel mixture off the exhaust temp.
    Being as Yamahas run hotter then others he sets them up 180-185 F. In general getting them all the same temp.
    Using the temp gun he points the beam at the first bend coming of the exhaust pipes.
    Sounds feasible for a rough set of the fuel mixture.

    Anyway time to get ready for the ride to work! :rolleyes:
     
  12. XJ550H

    XJ550H Well-Known Member Premium Member

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    epa requirements made it so our bikes run lean at Idle may be a pilot jet change or pilot air jet change would make the gunson work better for some bikes.
     
  13. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    It's not the tool, and it's not your eyes. Even though you've rebuilt the carbs there is still something wrong.
     
  14. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    The tool works fine with stock jets.
     
  15. waldreps

    waldreps Active Member

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    Maybe so but there's no way I'll ever fix it since I did everything precisely to the instructions in the Church of clean. I bought the deluxe rebuild kit from Len, including tools needed, and watched the videos and asked questions on here and have had the carbs off 2 or 3 times after that to double check things and make sure they were right. There's no way for me to get the carbs any more correct than they are except for setting the mixture adjustment. I'm not sure what else it could be that would make the flame not react like others say it should. I'm by no means saying that I'm perfect or trying to be rude. I appreciate the help and I'm sure I'll need more in the future. I just don't see how I could have been any more thorough or correct when doing my carbs. Thanks for the help.
     
    Last edited: Jun 4, 2017
  16. waldreps

    waldreps Active Member

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    Can somebody out there shoot a short video of the flame while you're doing the adjustment with the Colortune on an XJ650? I think that would help me a lot to see how it works on another similar bike and where you actually set it in the flame range.
     
  17. tabaka45

    tabaka45 Well-Known Member

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    I'd still start with the pilots set at about 1 3/4 and new plugs and adjust from there. If you get the plugs all light brown or tan then you've got it.
     
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  18. Justin Hardy

    Justin Hardy New Member

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    Hey, no hijack intended, just want too say thanks for the tips il be needing this. The other day I did what some people on here said because the xj are difficult and pre 1985, as soon as it changes from yellow too blue stop adjustment, I did this and all plugs are black fouled carbon. I guess it's wayyyy too rich and is messed my plug up. So il try the white too blue method, thanks
     
  19. Timbox

    Timbox Well-Known Member

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    I too plan on doing the color tune this week, will let you know how it goes.
     

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