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Oil on Spark Plug ... what to do next?!

Discussion in 'XJ Technical Chat' started by Jdtrumpet, Mar 23, 2019.

  1. Jdtrumpet

    Jdtrumpet New Member

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    So I am fine admitting that I am a complete NOOB to most engine work on a car or bike. I am a tinkerer and generally know how things work. This means that I tend to do a ton of research before I get going on a job and then tend to do ok with it... BUT I am having issues with this one.

    The other day I started up my 83 Maxim for the first time after winter and it was running rough. I then proceeded to clean out the carbs with Seafoam, etc. assuming it was gummed up from the winter. After some more digging I found out that cylinder #4 wasn't firing at all. (3/4 would make it run rough!)
    After taking out the spark plug, I noticed it was covered in oil at the bottom and also noticed a small pool of oil under the bike the next morning when I went back to work on it again. I haven't found the source of the leak yet, but did replace the spark plug. It works for now, but obviously I need to fix this!

    So, I've looked around and seen various ideas of what to do. My question is what I should start with, instead of completely re-doing everything (which would take me forever since I don't REALLY know what I'm doing).
    Should I just start with the Valve Cover Gasket? If I open it up to check what is going on, do I immediately have to replace the gasket, or can I just look around and put it back for now?
    Also, I'd like to avoid changing the valve stem seal because of the extra tools, etc.
    BUT, I am open to suggestions. What are your thoughts?
     
  2. k-moe

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

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    Look for where the leak is coming from.

    If oil is all over, then clean the engine, let it dry, and dust it with talc before running the bike.
    The talc will abosorb the oil and make it easier to see.
    Some oil leaks won't show themselves at idle.

    Don't fix anything until you know what's broken.
     
  3. Jdtrumpet

    Jdtrumpet New Member

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    Well there are two leaks (possibly one).
    1. I know one is leaking out of the bike onto the ground
    2. I know one is leaking into spark plug #4 (the one I am most worried about)

    Shouldn't I try to fix the spark plug issue first? And I'm pretty sure talc would NOT be recommended for inside the engine...haha!
     
  4. XJ550H

    XJ550H Well-Known Member Premium Member

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    is your spark plug tip oily as well or just the external parts of the plug?

    when considering changing your valve cover gasket also replace the donuts on the bolts that hold down the cover.
    I would re place the donuts if after inspecting a few the rubber was all cracked or hard.
    then consider the valve cover gasket. it may still be good.

    when you have the cover off check your valves clearances that way you button it up for the next 5k miles.

    do the talc powder thing it will show where the oil leaks from , valve cover or cylinder head gasket.
     
  5. k-moe

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

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    The spark plug being wet with oil could be from three things.
    1. worn rings.
    2. hardened valve guide seals.
    3. stuck rings on that cylinder (likely ince the bike may have been sitting for an extended period of time).
    Again, diagnosis must occur before any repair can be attempted.
    Have you performed a compression test?

    The external leak should be addressed as well, but you still need to know where it is coming from before you start throwing parts on and hoping that it gets fixed.
     
    Last edited: Mar 24, 2019
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  6. XJ550H

    XJ550H Well-Known Member Premium Member

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    oil leak out of bike and onto ground. could be many things ,oil filter cover, drain plug in need of new crush washer, oil level sensor the list gets longer it could also be the oil from vc gasket or cylinder head gasket leak.
    need more info location
     
  7. Timbox

    Timbox Well-Known Member

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    Pick one issue first, I would go with the piston and see if k-moe is right. I would also agree that it might be stuck rings from sitting over the winter. 1/2 Auto trans fluid and 1/2 acetone into that cylinder for a few days should free up any ring issues.

    If you have a compression tester that should be the first test you do.
     
  8. Rooster53

    Rooster53 Well-Known Member Premium Member

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    A common issue with bringing these bikes out of winter storage is a leaky / sticking float needle valve that causes fuel to overflow and foul the plug. This is particularly true if proper maintenance to the carbs has been neglected. Are you sure the plug wasn't just wet and fuel fouled from excessive fuel from a malfunctioning carb #4?

    How much have you run it since installing the new plug?

    Also, be sure to check the oil level and make sure it has not been contaminated with fuel. If the oil is contaminated with gas it can either cause leaking from the seals because of the fuel thinned oil or it can produce blow by into the air box which will then leak onto the ground near the center stand.
     
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  9. Polock

    Polock Well-Known Member

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    run it for awhile, see what that plug looks like then. how old was that oily plug, what makes you think it had oil on it, not just gas from not firing.
    the oil leak is probably the valve cover gasket from 1983. get a gasket and donuts for it and check the valves before you put it back together
     
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  10. Jdtrumpet

    Jdtrumpet New Member

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    1/2 trans fluid and 1/2 acetone to fix this?? So how do you go about this? Drain oil, valve cover off, pour in and let it sit, then what? Intrigued but that sounds like it could mess stuff up if I do it wrong!
     
  11. Jdtrumpet

    Jdtrumpet New Member

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    [QUOTE="Rooster53, post





    Also, be sure to check the oil level and make sure it has not been contaminated with fuel. If the oil is contaminated with gas it can either cause leaking from the seals because of the fuel thinned oil or it can produce blow by into the air box which will then leak onto the ground near the center stand.[/QUOTE]

    This sounds like the most possible right now because of where the oil leak seemed to be from. I’m going to run it for a bit and then get back to checking when the weather gets better again!
     
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  12. k-moe

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

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    Just put a tabelspoon of the mix down the sparkplug hole. Nothing needs to be drained beforehand, and nothing needs to be removed after.
    This is a method that has been used (with variations in the solvents used) for over 100 years.
    The acetone helps the oil creep into the small places, and the combination breaks up any corrosion or sludge that may be keeping the piston rings from expanding into the bore properly.
     
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  13. k-moe

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

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    Open the oil fill cap and smell the oil. If you smell any hint of gasoline than you had better not run it at all until the fuel leakage problem is fixed (if such a problem exists). This is a problem that will lead to very bad (and very expensive) things happening if left alone.
     
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  14. Jdtrumpet

    Jdtrumpet New Member

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    I thought I would send a quick update. It seems like the weather has helped my issue! I have been running the bike the past two weeks with no issue at all. All of the cylinders are firing and no oil or gas on plug #4. I'll be doing some work on this puppy throughout the season to ensure that doesn't happen again. Thanks for the help everyone!
     
  15. k-moe

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

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    A change in weather has no bearing on oil being on the sparkplug, or not being on the sparkplug.
    Did you ever check the oil for gas contamination?
     
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  16. Jdtrumpet

    Jdtrumpet New Member

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    What I meant was that the stuck valve guide became unstuck when the weather warmed up and the engine was in regular use again. No gas contamination at all, which is great! Not saying the problem is solved, but now I have all 4 cylinders and will be able to fix much easier this summer.
     
  17. k-moe

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

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    There was no mention of a stuck valve guide, or of a valve that was hung open.
    I think we have a terminology problem, because you can't see the valve guides without removing the cams and valve shim buckets.
    It is possible (likely really, given that the contamination has cleared up with use) that a valve guide seal is leaking, but the weather won't make that better either.
    The good news is that replacing the valve guide seals is possible without removing the head.
     
  18. Jdtrumpet

    Jdtrumpet New Member

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    sorry, forgot to type one word... an important one! The valve guide SEAL. I do plan to fix this even though it is running like a beaut right now. Thanks as always K-moe!
     
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  19. k-moe

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

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    Do you knw how to use a length of rope to hold the valve in place while the keepers are removed? Makes the whole job able to be done without opening anything but the valve cover.
    As a temporary measure you can run a stop leak (ATP AT-205 Re-Seal is my preference ) to help the seal soften enough that it might not leak when sitting.
     

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