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  1. #1
    Duke's Avatar
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    Single layer head gasket ?s

    OK, try to help me understand why a single layer head gasket would be more prone to leaking then the OEM double. The answer " Because Yami does it that way" is unacceptable.

    I have always used single layer (New everytime) and never had a problem. Always pressure test and use Coppercoat. Looking at the single layer there is more then enough material to absorb minor defects in the head/cylinder deck surface. I check the 3 cylinders with an 18" machinest straight edge along with the head/heads.

    Also can someone explain to me how water would intrude the cylinder even if the gasket failed. Whenever I lost an O-ring on my race boat the cylinder pressure would push all the water out of the water jackets and steam out of the pissers. Immediately you know what happened but never did water intrude the cylinder. How can this happen. Very little water pressure there and a great deal of cylinder pressure.

    Just looking for help understanding. Right now I just don't see it. To me this seems like a better solution for a tighter squish verses having the cylinders decked and risking a chip on the nick coating.


  2. #2
    Duke's Avatar
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    And to add to my original post. The new OEM gasket seperated measures .009 at the flat area in between the heads and .019 accross the cylinder area where the raised rings are. Thats .010 of compression and defect absorbtion. In my narrow little mind I don't see how this could leak unless something is really out of skew. But I am up for reasons I can't see.

  3. #3
    Chine Walker
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    Duke:
    When you separate the gasket; which side/half do you use? One has #'s stamped on it the other doesn't. I guess the rivets have to be ground out to separate, right?
    Thanks,
    jpj

  4. #4
    Duke's Avatar
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    I just drill the rivots out.

    On the 1200 I use either the top or bottom but not the middle and on the 1300 I use either. All have the same size indentions around the cylinder.

  5. #5
    Moderator Insanediego Joe's Avatar
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    I think if the leak from the head is bad enough it will spit water into one of the carbs causing a real problem. Hydrolock, bent rods and such. IMO humble opinion (having raced endurance) Its just not worth it. Matbe a rec rider can get away with it.

  6. #6
    Duke's Avatar
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    Quote Originally Posted by Insanediego Joe View Post
    I think if the leak from the head is bad enough it will spit water into one of the carbs causing a real problem. Hydrolock, bent rods and such. IMO humble opinion (having raced endurance) Its just not worth it. Matbe a rec rider can get away with it.
    That could be true but given the data I don't understand why 2 would be better then 1. Thats the answer I am looking for. Wouldn't 2 gaskets have another area of possible failure?

  7. #7
    Moderator Insanediego Joe's Avatar
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    Your getting above my pay grade here but lets turn the cup over and look at it like this. wouldnt 2 layers be double the protection against failure. If the machined surfaces are slightly warped or imperfect wouldnt 2 layers absord more of that imperfection than 1? I am truly asking cause I really dont know the answer.

  8. #8
    Duke's Avatar
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    Quote Originally Posted by Insanediego Joe View Post
    Your getting above my pay grade here but lets turn the cup over and look at it like this. wouldnt 2 layers be double the protection against failure. If the machined surfaces are slightly warped or imperfect wouldnt 2 layers absord more of that imperfection than 1? I am truly asking cause I really dont know the answer.

    I can possibly see that but having a .010 raised area around the cylinder shouldn't that be enough? Certianly thats more pressure on the deck surface then an O-ring head. Also I didn't realize the possible leak could be on the outside of the head dripping into the carbs. My thinking was the gasket would fail on the cylinder combustion area first.

    As far as Endurance racing goes we ride 80miles in an afternoon racing WFO side by side through the turns. Raced CC for several years and actually think this is more demanding on a boat then that was. Not really sure how endurance racing is now.

    Not arguing with ya Joe just trying to understand.

  9. #9
    One day at a time..... N8R's Avatar
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    i had single layer gasket and ski blew at 12 hrs Jim said it was do to single gasket and running the stock SS... i really dont know but, i have put over a 100 hrs on it since with double gasket and Freeflow with no probs(thank god and Jim) but, lately i have bee tempted to go back to single and see...of course i dont know squat about GPRs as others have pointed out

  10. #10
    Moderator Insanediego Joe's Avatar
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    Quote Originally Posted by Duke View Post
    I can possibly see that but having a .010 raised area around the cylinder shouldn't that be enough? Certianly thats more pressure on the deck surface then an O-ring head. Also I didn't realize the possible leak could be on the outside of the head dripping into the carbs. My thinking was the gasket would fail on the cylinder combustion area first.

    As far as Endurance racing goes we ride 80miles in an afternoon racing WFO side by side through the turns. Raced CC for several years and actually think this is more demanding on a boat then that was. Not really sure how endurance racing is now.

    Not arguing with ya Joe just trying to understand.
    You with out a dought would know better than me.


    Rough water racing man , the hooking and unhooking the loading and unloading the unknown water pressure going through the head at the second the pump reloads? Compared to wot smooth water where everything as far as pressure and loads are stable for miles on end. I think we are starting to compare apples to oranges here? I am sure you have more hours running a single layer than I do running a double layer. My ski was a tripple piped ski with after market oring heads. I really just dont know and really cant comment any further . This is as far as my expeirience will take me. I just dont want to give out bad info on my part.

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