Engine Trouble HELP, new plug, running problems

Discussion in '2-Stroke Engines' started by alpha, May 4, 2012.

  1. alpha

    alpha Member

    i went and bought a b6hs and now the motor suddenly stops running after 5 min, is it running to hot or what never had this problem:dunce:
     

  2. motorpsycho

    motorpsycho Active Member

    are you sure that you've got a good flow of fuel into the carb?
    It could be a fuel issue, like the float bowl may be running out of gas and slowly re-filling.
    either the fuel flowing out of the gas tank os restricted (junk in the petcock), you have a clogged fuel filter, or junk in the needle & seat on the carb.
    I don;t think the new plug has anything to do with it, but you could put your old plug back in and see if it does the same thing.
    If it does the same thing with the old plug, then it's probably a fuel issue.
     
  3. DeathProof

    DeathProof Member

    i agree put in the old plug and see if the bish still has problems
     
  4. alpha

    alpha Member

    i dont think its that cause its only once the motor warms up, and it gets harder and harder to pedal but ill give it a shot
     
  5. alpha

    alpha Member

    its like someone hit the off switch
     
  6. Al.Fisherman

    Al.Fisherman Active Member

  7. alpha

    alpha Member

    never mind i pulled off the top of the engine off, and the cyl walls are gouged and theirs bits of round metal that look like pins or something, like roller bearings or something. but now i know why its not running, wonder what it sucked up?
     
  8. Al.Fisherman

    Al.Fisherman Active Member

    Pull the wrist pin and look there. Most likely that's where it came from.
     
  9. alpha

    alpha Member

    on top of the piston though how would they get up that far
     
  10. alpha

    alpha Member

    how small would they be, these are very small, like 1mm diam. and 2-4mm long
     
  11. Al.Fisherman

    Al.Fisherman Active Member

    http://www.shkdbearings.com/html/skf/2004044626/bearings-shop-70762-SKF.html
    They can break up into small pieces and transferred to the combustion chamber through the transfer ports. There are only two places they can come from, assuming that they are in fact bearing pieces. From the wrist pin or the rod bearing. Length new is 7mm, thickness depending on the manufacture (number of bearings used).
     
  12. alpha

    alpha Member

    so whats the best way to figure out what it was and were do i get replacements
     
  13. alpha

    alpha Member

    i looked at your breakdown ron, i see the one on the wrist pin with the piston, i just find it hard to belive one of those came apart. that has to be extreme. and i found a replacement at gasbike.net for what i believe is the wrist pin bearing. i also have a parts motor so ill have to still get a new piston and cylender and head.
     
  14. Al.Fisherman

    Al.Fisherman Active Member

    Actually it's common, when that bearing goes out. The pieces are so light they get tosses all over, even sucked into the combustion chamber. Broken rings are also common. Luckily I've never had any problem, but my son broke a ring in his engine within the last two weeks. Clean the engine out good and take a pencil magnet making sure you get the remaining pieces out.
     
  15. motorpsycho

    motorpsycho Active Member

    if they are roller bearings, they can get past the the piston and rings and make it to the top of the engine beleive it or not.
    Someone just had this same problem not too long ago, and I didn't beleive it until I saw it for myself.
    Pictures tell a 1000 words....post some if you can.
     
  16. alpha

    alpha Member

    well without taking pics, the top looks like my son got ahold of a paper clip and playdoh and poked it a buch of times, and the piston looks like the same except the pins are also sticking out of it like a 5 oclock shadow and the cyl walls are scratched pretty bad, hope that is a visual for you
     
  17. motorpsycho

    motorpsycho Active Member

    this is probably way off because you are using a b6hs plug (which should have the correct reach) but are you sure that the plug isn't hitting the top of the piston?
    It shouldn't be, but you never know.
     
  18. tooljunkie

    tooljunkie Member

    i remember back when my buddys truck got stolen when he got it back engine was blown.found pieces of piston in the air cleaner.
    when things go bad there's no telling where loose pieces will end up.
     
  19. motorpsycho

    motorpsycho Active Member

    I'm sorry but there's probably no way possible for peices of a piston to end up in the air cleaner. (in a naturally aspirated engine)
    The piston chunks would have to get past the intake valves, through the curves of the intake manifold runners, up through the throttle plates of the carburetor, up through the carb venturi, and then up into the air cleaner.

    UNLESS the engine totally blew all apart in a million peices, and the piston peices just happened to get shot through the sides of the air cleaner housing by coincedence.
     
  20. tooljunkie

    tooljunkie Member

    whilst in persuit of stolen 1979 chev 3504bbl,the thief didnt know enough to shift it into D from low.70mph in first gear was enough to do it.it was a fresh rebuild,when it scattered it left pieces everywhere,it dropped a valve,making a large opening for piston chunks to go,as well as throttle held wide open.had the valve springs been replaced with high-performance ones,they never would've floated.even broke the fuel pump off.
     
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