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    Plug Chop Input Please

    OK I pulled my new plugs when I got home. They were ridden for about 22 miles today.

    The plugs have a golden brown/light tan rim and and a light grey tip with a white core element.

    What does this say to you? Sounds like "Normal" according to the manual.

    Weird thing is though unless I lost count during my frustration filled carb tuning attempt they are 2.5 out on cyl 1 and 3 out on the rest....

    #2
    If by "white core element" you mean the ceramic insulator, then white is too lean. Pics may help?
    You also need to chop off at a specific throttle position and under some kind of adequate load to get the most accurate plug read. Throttle position depends on which jetting ciruit you're trying to analyze. Allowing the bike to idle, even a little, will compromise the reads. The bike should be tested on an uphill road if at all possible. Some kind of load is what you want.
    22 miles is more than enough to color the plugs well if the bike is running correctly. I assume the plugs are the same factory recommended heat range and gapped correctly.
    Is the bike totally stock?
    As for mixture screw uniformity, because of small differences in each cylinder, the mixture screws purpose is to allow fine tuning of the pilot circuit for each cylinder. Sometimes a correctly jetted bike will have all 4 screws close to the same setting. Sometimes the screws will be set a little different from each other to get an even plug burn. I wouldn't personally worry over a difference of 1/2 turn but not more than that. More would suggest something else may be wrong and the larger different settings are necessary as compensation for another problem. If you know for a fact that you serviced each carb the same and the cylinders, etc, are in general good condition, then I think you can accept a difference of 1/2 turn as normal. I've seen bikes come straight from the factory with their screws set 1/2 turn differently from each other.
    Just to be fair, on the other hand, it could mean you missed something, but I'm just saying it sounds normal.
    Any other symptoms that suggest lean? Surging or hesitation? Slower than normal to warm up, etc?
    And on the seventh day,after resting from all that he had done,God went for a ride on his GS!
    Upon seeing that it was good, he went out again on his ZX14! But just a little bit faster!

    Comment


      #3
      Originally posted by KEITH KRAUSE View Post
      If by "white core element" you mean the ceramic insulator, then white is too lean. Pics may help?
      You also need to chop off at a specific throttle position and under some kind of adequate load to get the most accurate plug read. Throttle position depends on which jetting ciruit you're trying to analyze. Allowing the bike to idle, even a little, will compromise the reads. The bike should be tested on an uphill road if at all possible. Some kind of load is what you want.
      22 miles is more than enough to color the plugs well if the bike is running correctly. I assume the plugs are the same factory recommended heat range and gapped correctly.
      Is the bike totally stock?
      As for mixture screw uniformity, because of small differences in each cylinder, the mixture screws purpose is to allow fine tuning of the pilot circuit for each cylinder. Sometimes a correctly jetted bike will have all 4 screws close to the same setting. Sometimes the screws will be set a little different from each other to get an even plug burn. I wouldn't personally worry over a difference of 1/2 turn but not more than that. More would suggest something else may be wrong and the larger different settings are necessary as compensation for another problem. If you know for a fact that you serviced each carb the same and the cylinders, etc, are in general good condition, then I think you can accept a difference of 1/2 turn as normal. I've seen bikes come straight from the factory with their screws set 1/2 turn differently from each other.
      Just to be fair, on the other hand, it could mean you missed something, but I'm just saying it sounds normal.
      Any other symptoms that suggest lean? Surging or hesitation? Slower than normal to warm up, etc?
      I will snag some batteries for the camera for pics. The white insulators are white still yes but they were new plugs and I only put 22 miles on them.

      Jetting is all stock and the 22 miles were two separate 11 trips, one to work then one home where I pulled the plugs (Which I will do again tonight).

      I am not sure what could be wrong with the carbs that would cause all 4 plugs to read the same (lean?) but at 2.3/3 turns out the bike should be (and was) rich. So what could have changed magically by itself to make it lean on all 4 cylinders?

      I do have surging and hesitation during the first minute or so of a cold ride then it runs like a champ even the popping is 99% gone....

      Comment


        #4
        You said you attempted to tune the carbs. What was done?
        You said it was running rich before. How did you determine that?
        Is the bike stock?
        And on the seventh day,after resting from all that he had done,God went for a ride on his GS!
        Upon seeing that it was good, he went out again on his ZX14! But just a little bit faster!

        Comment

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