Engine Trouble spark plug shot out of head

Discussion in '2-Stroke Engines' started by nishikidrift, Oct 10, 2015.

  1. nishikidrift

    nishikidrift Member

    I fixed my engine air leak, went for a ride (forgot to tighten plug:idea:) and the spark plug vibrated loose and shot out threads are fine. now the engine wont start. I have spark and fuel any ideas?i have drained the bowl and made laps trying to start it.
     

  2. jaguar

    jaguar Well-Known Member

    probably cracked the conductor inside the plug. get a new one
     
  3. nishikidrift

    nishikidrift Member

  4. crassius

    crassius Well-Known Member

    first step is to see if you have spark (wire, cap, or CDI could have been damaged)
     
  5. nishikidrift

    nishikidrift Member

    In the first post i stated that the spark is fine. just checkit spark again just to be sure i had the plug at different angles to se if there was somthing loose and the plugs (i tested wit more than one.) is fine this also check if the wire shorted not the case.
     
  6. jaguar

    jaguar Well-Known Member

    it can spark outside of the engine but if the spark is weak then it won't spark inside the engine due to the compression which demands more spark voltage
     
  7. nishikidrift

    nishikidrift Member

    I'm in Portland,Oregon,U.S.A if that helps anything. the spark is strong. i understand that hemispherical compression plays a role in the spark's strength. the density of the air and fuel under compression can inhibit the ability for the spark to ignite the fuel. I have taken the carb off, drained it and peddled around for a while draining any flooding that could have happened in the cylinder, then made sure the exhaust was empty and dry (short of a lighter to burn off any remaining oil and fuel.) I don't know what's wrong with this engine.
     
  8. jaguar

    jaguar Well-Known Member

    Insure you have good compression. Plane the head and make your own gasket out of gasket material which will seal much better than the original aluminum one.
     
  9. butre

    butre Well-Known Member

    if the plug shot out it could be a cracked head.
     
  10. nishikidrift

    nishikidrift Member

    Could I do that with a sheet of sand paper and a plate of glass?
     
  11. jaguar

    jaguar Well-Known Member

    yes you can.
    but now it is essential you throw away the standard gasket. Being aluminum it can only conform once to the imperfections of the head.
    make your own, it's not hard to do
     
  12. nishikidrift

    nishikidrift Member

    so i still havent gotten this engine running and i have an other with similar issues minus the spark plug rocket, speaking of the plug they both are wet.
     
  13. jaguar

    jaguar Well-Known Member

    DON'T GO CRYING IF YOU DON'T TAKE THE ADVICE OF EXPERTS HERE.
    I'll bet you haven't planed the head and made your own professional gasket (well, anything is professional compared to the stock aluminum one).

    Me an expert? well, I have been into motorcycles since 1973 with my Penton 125 and have owned about 10 different bikes.
    People ask advice and then don't take it, thinking they are smarter than the old timers who give advice.
     
  14. nishikidrift

    nishikidrift Member

    Its nothing like that Jag:eek:, I'm on a limited in come and need to wait until I have the funds to get a glass cutter. the glass can get free off and sandpaper (what grit should I get?) copper sheeting(thickness?) for the gasket and micrometer. so I thought I would see about the wet plug issues while I save funds for the supplies AND YOU=YES I DO LISTEN TO MY ELDERS,SIR!!!wich is why I have not hooked up my jag C.D.I that i researched for a month before I bought. understand you getting upset about people not listening when they ask for help and advice then don't take any of it and that's not the case here! I figured i might be able to move through other issues as to not stall out.

    logically my head says i should find the lowest spot on the head and plane to that.
     
    Last edited: Oct 14, 2015
  15. jaguar

    jaguar Well-Known Member

    cool but be aware that head sealing is critical. It can't take a backseat to other things you might want to do.
     
  16. nishikidrift

    nishikidrift Member

    would using a soda can be too thin for a gasket? I saw one youtube ( https://www.youtube.com/watch?v=ReOuiYMcar8 ) a guy demonstrating this with a running engine,this I understand will boost compression as will the head planing but will it be too much compression? by the way i can get 3 gaskets out of on can and what about layering 2 can gaskets for thickness?
     
  17. jaguar

    jaguar Well-Known Member

    yes that is much too thin.
    planing down the irregularities in the head surface does little to increase compression.
     
  18. butre

    butre Well-Known Member

    with a properly mated head a soda can works
     
  19. nishikidrift

    nishikidrift Member

    What is the thinnest I should go for head material without shaving the head to gain compression? What grit sand paper should I use for planing? It looks like this weekend ill be getting to get this done... i just pulled my head and i think my cylinder is flooded so, I'm for the night in going to leave the head off so it can evaporate and dry out.

    p.s. yes I'm a neophyte.
     
  20. jaguar

    jaguar Well-Known Member

    a "properly mated head" for use with such a tin gasket means taking the head and the cylinder to a machine shop to lathe them both perfectly flat.
    Doing it yourself with sandpaper and glass does not make a perfectly flat surface, but good enough for use with good gasket material which you don't seem inclined to use.
     
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