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Valve cover gasket

Discussion in 'Hangout Lounge' started by blackthunder, Jul 14, 2010.

  1. blackthunder

    blackthunder Member

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    On a scale of 1 to 10, how difficult is it to replace the valve cover gasket?
    Also, any tips to make the job go smoothly?
     
  2. iwingameover

    iwingameover Active Member

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    if you don't break/strip any bolts and it was done correctly the last time it's a 0 on a scale of 1 to 10 in easyness.

    cleaning the old one off is the hardest part if nothing breaks/strips.

    Check your valve shims while you're in there.
     
  3. Metal_Bob

    Metal_Bob Active Member

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    If you are replacing it because it's leaking/seeping, you probably also need the rubber boots for the bolts that hold the cover down. Apparently that is the source/cause of most leaks besides a worn/ripped valve cover.

    Chacal sells them

    Somewhere this is also a picture post showing how to check valves and reseat the valve correctly and professionally for an easy remove of the cover next time.
     
  4. iwingameover

    iwingameover Active Member

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    the valve clearnace write up is in the XJ FAQ SUGGESTIONS section.

    Not all bikes have the donuts. My 81 650 does not.
     
  5. Militant_Buddhist

    Militant_Buddhist Member

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    His Seca (and mine) however, does have the donuts on the bolts.

    As a stopgap (really dirty hack, I know) I tucked some rubber O-rings from the faucet department of the big box hardware store under the donuts. This took my massive oil leak (about half a quart every 1k miles) down to next to nothing. (3/4 of sightglass to 1/4 in a 4k oil change interval)
    I can't in clear conscience recommend this to anyone else as I suspect it has the potential to cause undue wear (read as cutting) of the gasket.

    This reminds me, is there a different gasket available that has the 'D' shapes for the camshaft as separate pieces the way many later XJ's do? I imagine such a gasket would be cheaper since it would be one flat piece plus the little 'D's rather than a single large gasket that incorporates this extra shape.

    (ok ok so I could just ask Chacal but I thought it'd be nice to "publish" the query)
     
  6. bigfitz52

    bigfitz52 Well-Known Member Premium Member

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    The gasket with the separate half-moons is the "conventional" gasket used on the non-YICS motors.

    The YICS motor's gasket is the complex affair with the "D's" molded on.

    The "donuts" are KEY to the YICS gasket's effectiveness; the bolts have stop collars that keep them from being tightened past a certain point. The bolts push down on the "donuts" which push the cover against the gasket. Once your donuts are baked hard and permanently compressed, they will no longer do the job and even a new gasket will leak.

    All that being said, once the gasket and donuts have been replaced on a YICS motor, you can R&R the valve cover many times over without needing to replace anything again for a long while.

    The non-YICS motor has a conventional paper gasket with "normal" bolts.
     
  7. blackthunder

    blackthunder Member

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    Thanks, this can be done with the engine still on the bike, right? Just a matter of simply removing the tank and then I should have access to the bolts, correct?
     
  8. iwingameover

    iwingameover Active Member

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    Yes. You'll also want to tie the spark plug wires above the frame rail to keep them out of the way. And I had to unbolt my horn but it's not a stock one so I don't know if that matters with a stock horn.
     
  9. mikeames

    mikeames Member

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    Would the XJ1100's be different than you mention above? I have an '82 XJ11100 and it currently has the paper gasket (leaking) and regular bolts (not leaking around the bolts).
    Do I have the wrong valve cover and/or gasket? I came by this thread looking for the secret to making these things not leak. I replace the gasket once but it leaks. I should probably have checked the cover for flatness first...
     
  10. hogfiddles

    hogfiddles XJ-Wizard, Host-Central NY Carb Clinic Moderator Premium Member

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    I have also found on my bike, and on another person's bike (83 xj650 and an 85 xj700) that the corners of where the D's are on the head, there is a sharp edge/burr to the casting and it can cut the rubbber gasket right on the corners due to the sharp edge. So, I have used a very fine mill file and just "kissed" the edge/burr to make it smooth to the touch. Then, I put a very small dab of black rtv at all four points, and I haven't had another leak.

    Dave Fox
     
  11. schuchman

    schuchman New Member

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    I have had constant issues with the gasket leaking. I pulled the tank, head cover, horn and some electrical stuff. Originally, I was leaking from the the front of the bike. I decided to replace the gasket and that leak went away, but a new one developed at the Ds on the right side. I removed the everything again and resealed with Ultrablack. I bolted down the cover and let it sit for a week. Once I fired up the bike, after about 10 minutes it started coming out again. Very frustrating. I am not sure what my next step should be.
     
  12. iwingameover

    iwingameover Active Member

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    Did you replace the D's and the rubber donuts on your bolts?
     
  13. schuchman

    schuchman New Member

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    The Ds were attached to the Gasket. But not the rubber donuts. Mine actually have a metal ring on them as well. Could worn out Donuts prevent the bolts tightening the cover down enough?
     
  14. bigfitz52

    bigfitz52 Well-Known Member Premium Member

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    Yes. Those "donuts" are what actually push the cover down, as the bolts themselves have stop collars on them to prevent overtightening. (The "donuts" are a composite part, the metal washer is bonded to the rubber.)

    If the "donuts" are all compressed and baked dead, then they won't hold the cover down tightly and even a new gasket will leak.

    Good new is, once they and the gasket have been replaced once, they are good for many more service cycles. I've had mine off/on my '81 at least 2 or 3 times since fitting the new parts, still sealing tight.
     
  15. schuchman

    schuchman New Member

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    Do you pull the rubber donut way from the washer before cutting it off?
     
  16. bigfitz52

    bigfitz52 Well-Known Member Premium Member

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    You can, I just CHOMP thru them with a pair of oversized diagonal cutters and then twist the remains off. The rubber won't separate easily, you would have to cut it and it's not worth the effort.
     
  17. parts

    parts Member

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    Even though I could not afford the donuts when I replaced
    the v/c gaskets you should do it.
    Mine does not leak at all but that was pure luck-I have
    to keep a real close eye on her just incase they fail.
    And go the extra mile for things like gaskets, seals, and get OEM.
    I'm no fan of the high cost but some things are worth the better
    quality that yamaha provides.
     

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