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Black sooty dry sparkplug

Discussion in 'XJ Technical Chat' started by Jostein, May 8, 2018.

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  1. Jostein

    Jostein New Member

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    Hi all. I have a 1983 xj750 Seca.
    I recently had the bike in the shop and had a service and synchronization of the carbs. Bike runs OK but is hard to start cold. I replaced sparkplugs today and noticed that the outer sylinder plug on the throttle side is sooty,dry black. The rest of the plugs are fine. I don't want to start adjusting on the carburetor but are wandering if one sparkplug can be bad or if something else is wrong.
    I appreciate any advice on the subject
     
  2. k-moe

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

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    You're going to have to. A bad sparkplug would be wet and not at all sooty.
    Given that she's hard to start when cold, I'm suspecting that cylinder (at least) is a tad rich.
     
  3. Jostein

    Jostein New Member

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    Thanks k-moe . I am a dummy with carburetors . Is there a detailed description /pics of where adjustment screws are and which one to turn in or out?
    There must be one for air and one for fuel? If I can get instructions for dummies I will try :)
     
  4. kosel

    kosel Active Member Premium Member

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  5. Jostein

    Jostein New Member

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    Thank you so much kosel :)
    I will try to adjust. Is it in or out for a leaner fuelmix.?
    I ordered a kit from gunson. It's a sparkplug with a glass plate which allows you to check the combustion color and adjust the fuel/air . I'm exited to try. Will come back with a happy end I hope.
     
  6. Chitwood

    Chitwood Active Member

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    In=leaner, out=richer
     
  7. Jostein

    Jostein New Member

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    Thanks Chitwood. :)
     

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