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Pattern head gaskets

Discussion in 'XJ Technical Chat' started by Greenbike, Aug 17, 2014.

  1. Greenbike

    Greenbike Member

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    I put my cylinder head on, I put everything else on, I started the engine. The two middle cylinders were blowing. I took the head off again, and measured the gaskets. The camchain tunnel seal is 0.5mm (20 thou) thicker than the head gasket.

    This is from a pattern gasket set. I'm using the proper Yamaha head gasket and camchain tunnel seal when it all goes together again. The head is being taken to a place that can check to see if it's warped.

    Anybody else had this? It might just be a problem that is common to pattern gasket sets in the UK. Either way, I'm not impressed!
     
  2. 4freese

    4freese Member

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    I have used pattern gaskets in the past and have had no issues at all unless there was a problem with the head itself. I have had bad sets also where one or more of the gaskets were misshaped or damaged. I am in the US but I get many of my sets from overseas as they are hard to find here for the older bikes.
     
  3. a100man

    a100man Well-Known Member

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    Read this with interest as I'm about to replace the head gasket on the 600 engine I have, following a top end 'refresh'. The headgasket on the 600 though is all in one piece - is this different for the 550 ? Was going to get one from M&P products in wales.
     
  4. Greenbike

    Greenbike Member

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    a100man, you are not far from me; I'm in Milton Keynes.

    I've ordered the tunnel seal from Fowlers in Bristol. They are very helpful and send out stuff as soon as they can. I would inspect the new head gasket very carefully, but I don't think that most other engine gaskets, being paper, can be a problem.

    I didn't get the pattern gasket set from M&P's, but it carries the brand name Athena.

    The head is "dead flat to within 1.5 thou" (0.038mm) so I am much relieved. The tunnel seal will be here in eight or nine days.

    I don't know about the 550s.
     
  5. rocs82650

    rocs82650 Well-Known Member

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    Comparison measurement. New against old. Both have been torque compressed. What's the difference?

    Gary H.
     
  6. Greenbike

    Greenbike Member

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    No idea; I don't think that I have the old gaskets any more. After 30 years, the old head gasket did not come off in one piece. I shall measure the new ones before they go on, though.
     
  7. rocs82650

    rocs82650 Well-Known Member

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    PM or e-mail Len/Chacal. Ask for a measurement. Thank him proper.

    Gary H.
     
  8. a100man

    a100man Well-Known Member

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    Apologies - for some reason I assumed your's was a 550. Indeed in US terms we're practically neighbours..

    Cheers

    James
     

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