spark plug oil leak

Discussion in 'Motorized Bicycle General Discussion' started by sunkyman, Jun 21, 2008.

  1. sunkyman

    sunkyman New Member

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    Have any of you guys had this problem? The stock chinese GNT plug didn't have this problem, but the champion & ngk plugs both leak around the seal (ran like **** with the champion L86C, but it might have been a gapping problem). And yes, it's tightened all the way down. It doesn't feel like the fit is sloppy or anything. Do you think it is safe to use permatex on the threads of the plug to stop the blowby?
     
  2. deacon

    deacon minor bike philosopher

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    should there be one of those compression washers on it. I can't imagine oil collecting without a loss of compression in the cylinder
     
  3. sunkyman

    sunkyman New Member

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    Yes, there is a compression washer on it, but oil is definitely getting by it. And it looks and feels like the plug is completely seated. As for compression loss, I really can't tell. The motor is still in the breakin stage, so I've been attributing the lack of power to that. It runs pretty crappy for the first few minutes, then gets better as it warms up. I get about 2/3 - 3/4 throttle ok, but it loses power at full throttle. I have to back the throttle off to get back in the power band. Plug looks good, running 30:1 synthetic. I've just been figuring it still needs to be broken in. I did notice the head was leaking as well, but I fixed that. Had to put a couple washers on the studs so it would tighten down. Still trying to work out the bugs
     
  4. deacon

    deacon minor bike philosopher

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    You know with the price of spark plugs I would just go to the auto store and try a different one. It could be something wrong with the plug. That would be my first guess. Fix the easiest things first. If that doesn't do it move on. I don't think my plug has a compression washer. Some where on here is a list of compatable plugs. Try a search, if you cant find it let me know and I'll try.
     
  5. deacon

    deacon minor bike philosopher

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    here is one that they recommend


    NGK B5HS works great and they are inexpensive or maybe you could try the next range cooler B6HS, but supposedly the Chinese stock plug is equivalent to the hotter B4HS...which I don't agree with....but the stock plug is slightly different than the NGK in construction and electrode tip length.
     
  6. Walter F.

    Walter F. New Member

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    Don't know about your motor but 30to1 sounds wrong for break-in, from every thing I've heard 16to1 is what you need in order to get the rings to seat. That's for the first gallon or so. Give Pablo a shout, he's up on all the oily stuff.(c)Walter F.
     
  7. sunkyman

    sunkyman New Member

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    I've got the NGK plug in right now, but I guess I can try another one. I just figured that since both the NGK plug & the champion plug leaked...ARGH! And I ran the first gallon at 20:1, just for clarification. I'm still on my first tank of 30:1.
     
  8. deacon

    deacon minor bike philosopher

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    I didn't realize you had two plugs that leaked. I have no idea what it could be. You said the plug was tight and there was no visible signs of exhaust leak around the plug except for the oil. I just don't get it.

    It sure does sound like an exhaust leak there. You know the exhaust pipe leaks oil. You might ask at the auto parts store if there is a sealant that wont hurt the plug to use on the threads. Some anti seize stuff might help keep the exhaust from seeping around the plug but that doesn't sound all that reasonable either. Ask Norman in a private message and let us know.

    Im going to send norman a pm and ask him to take a look at this thread.
     
    #8 deacon, Jun 21, 2008
    Last edited: Jun 21, 2008
  9. Dave31

    Dave31 Moderator
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    Hmmm.... Thier might be a problem with the head thier that you are not getting a good seal between the plug and the head...It is a good ideal to use some thread anti-seize on the plug

    A pic of the head with the plug out may help to see what's going on :confused:
     
  10. Pablo

    Pablo Master Bike Builder & Forum Sponsor

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    I'm kinda agreeing with this. Nothing should be a-blowin' past the plug. I would get a new head gasket and then take the head off (spark pug first), and carefully check the plug mating surface.

    Should not matter what the oil mix ratio is.
     
  11. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

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    O.K., first of all, too much oil will not help the rings to seat. Running at various throttle and rpm settings will, but you need to seat the rings in the first tank of fuel or so to be done properly.

    Now, I have seen a very small amount of oil leaking by the plugs on a few of these, not a big deal, and may stop after some running.

    Don't use anything but anti sieze compound on the plug threads and avoid removing the plug from a hot engine.
     
  12. boogerballs

    boogerballs New Member

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    Could it be that after running it initially with the GNT plug, that the exposed threads in the combustion chamber filled with carbon deposits and won't allow the newer plugs, with possibly longer threads, to seat properly? Just something to check. Just measure the threaded area on each of the plugs to determine if the original GNT plug has shorter threads.
     
  13. Norman

    Norman LORD VADER Moderator
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    I think you all are talking about combustions reside leaking out around the sparkplug mainly past the threads/plug gasket. I have had this problem in the past and the only way to correct it was to go to a different sparkplug for some reason the sealing gasket starts to leak and over tighting it will result in a stripped sparkplug hole. The plugs gasket seems have a hairline crack in it gasket sealing area. I have had this on both champion and china plugs.
    What I did is clean off the threads in the head with either brake clean or carb clean while the head is still on the engine no need to take it off. I then get me a new sparkplug gap it and add a booger of neverseize to it and screw it in there is directions on how much torque to apply with a new gasketed plug which is different than on a ued gasketed plug so check with the manafacturer. I run the plug in by my fingers until it touches the gasket area then apply the torque to just crush the gasket something like 1/4 turn more if it a new plug less if it been used. champion has a site to look at for better info on this. I hate a leaking dirty engine as I'm the one who has to work on it and I'm picky that way becides a clean engine looks better. I hope this SB I wrote will help .
    Norman
     
    #13 Norman, Jun 22, 2008
    Last edited: Jun 22, 2008
  14. sunkyman

    sunkyman New Member

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    I appreciate all the input guys. I'll try another plug & try not to tighten it down so much, as per Norman's post I may have inadvertantly damaged the sealing gasket. I did check the thread length, and it is the same. This site is a great resource.
     
  15. thatsdax

    thatsdax Member

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    20:1 for Break in using Valvoline 2 stroke oil or equivalent. After break in ,go with AMSoil 2 stroke synthetic or equivalent mix 30:1. as For the first 50 miles, run 10 mins, let cool 10 mins. As for seepage around the spark plug, this is not a big deal and is common. If it is only a little. It is not a big deal at all. Use only a little anti seize on the threads. That is all. Enjoy the ride..
     
  16. Skyliner70cc

    Skyliner70cc New Member

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    Are you one of those folks who pulls a plug to check if carb mixture is correct? If so, those one time use crush washers will leak if reused.
     
  17. sunkyman

    sunkyman New Member

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    Yeah, I'm one of those folks. I guess that explains it.
     
  18. Skyliner70cc

    Skyliner70cc New Member

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    Oh, BTW, if you use anti-seize compound as Dax suggested, you must reduce the torque applied to the spark. THe factory torque setting (as most all other torque settings) are for dry threads, not lubricated threads. Antiseize compound requires anywhere from 25-33% less torque applied to the bolt. For example a 100 ft-lb torque specification becomes 70 ft-lbs with anti-seize.

    The lubricating effect of the liquid will not cause a properly torqued nut to loosen but it can cause you to over-tighten a bolt. Not a good thing in a aluminum thread such as the head in our engines.
     
    #18 Skyliner70cc, Jun 22, 2008
    Last edited: Jun 22, 2008
  19. Troy Dixon

    Troy Dixon New Member

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    Hey Guys,

    I Just put a NGK B7HS in and it started right up. Good to know it works.


    Troy
     
  20. Dave31

    Dave31 Moderator
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    Helo Troy Welcome to the forum :)
    :ride2:
     

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