Exhaust Exhaust Gasket Keeps Blowing Out Please Help

Discussion in '2-Stroke Engines' started by wackey101, Mar 3, 2011.

  1. wackey101

    wackey101 Member

    my bike keeps blowinng new gaskets from the bottom why is this
    i have changed the studs gasket and exhaust and it still blew my new gasket out from the bottom why is this

  2. GearNut

    GearNut Active Member

    Are you using the flimsy, not trust worthy, factory gaskets?
    Is the muffler flange perfectly flat; No bumps, ridges, dips or curves anywhere that the gasket makes contact to it?
    Is there any possibility that the way the muffler is mounted could put a pinching pressure against the gasket?
    Do you only have the muffler attached to the bike by means of the cylinder studs alone; Do you have a proper support strap between the muffler canister and bicycle frame to carry the weight of the whole exhaust system? Just hanging it by the studs alone is asking for troubles.
    Last edited: Mar 3, 2011
  3. wackey101

    wackey101 Member


    im using proper gaskets
    long street pipe corrctly attached no bumps on the flange like i said i tried it on two mufflers
  4. wackey101

    wackey101 Member

    whats the better gaskets
  5. GearNut

    GearNut Active Member

  6. retromike3

    retromike3 Member


    I had the same problem on my old motor so The first thing I did was to get a reinforced grade 8 mounting studs. and then I got a block and some 600 grit sandpaper and when the old studs were out I sanded the exhaust port flat. after that I got a alloy gasket and bolted it in. haven't had a problem since. and I have gone through two motors and still am using the same gasket.

    I got the parts from Sick Bike Parts.

  7. motorpsycho

    motorpsycho Active Member

    the cure is to get an aluminum exhaust gasket. from sick bike parts.


    Put a LITTLE bit of high temp gasket sealer on both sides of the aluminum gasket, and you won't have any more leaks or blown gaskets.
    The aluminum gaskets are also re-useable, and they are maleable enough that they form themselves to any irregularities on the pipe flange and on the cylinder flange.
  8. Flattracker

    Flattracker Member

    I too had the problem of blown out exhaust gaskets. I have bought intake, and exhaust gaskets from every seller on the internet and they all SUCK! They are cheap and inferior and have ALL FAILED on me! The aluminum one that needs sealing also!! The oil in the gas mix just pushes past the RTV sealant after a few miles of hard running. I also tried using permatex aircraft grade gasket sealant on them and it didnt work. I would have been better off buying a bag full of the cheap paper/rag gaskets. I got tired of changing a gasket every 10 miles and cleaning the mess off my bike and engine. I started by stoning the mating surface of the muffler perfectly flat using a whetstone and trans fluid. Then I cut out a new gasket from an old ford straight 6 4.9L intake/exhaust (single gasket coated grey) self sealing gasket I had. This Ford straight 6 engine, combination intake/exhaust gasket has a steel core and is coated with a heat activated sealing substance that seals when you run the engine. Its about 2mm thick I have not had a blowout, or oil leak from my exhaust port since I installed it 800 miles ago! It took more time to seal because the bike engine exhaust doesn't get as hot as a ford exhaust, but seal it did. I figured if its good enough for my ford well.....I did have a little trouble cutting through the gaskets steel. I didnt have tin snips so I used a hole punch set and heavy scissors. No more leaks for me.
    Last edited: Mar 25, 2011
  9. Dave C

    Dave C Member

    The new exhaust gasket from BGF is a exhaust gasket material with a steel core. It's light years better than the stock ones. I got two and used up a sanding roll in the Dremel matching one to the port.

    I haven't run the motor yet after the rebuild but they sure look like good gaskets to me. :helmet:
    Last edited: Mar 26, 2011
  10. motorpsycho

    motorpsycho Active Member

    sorry about that, but i got the aluminum gaskets and I have not had a blown out gasket or a leaky gasket since. They worked for me (and are still working), so I have no idea why they didn't work for you.
    I just have to comment on your quote "I figured if its good enough for my ford well....." If it's good enough for Ford, it still aint good enough....lol.
  11. Pablo

    Pablo Motored Bikes Sponsor

    The real trick to the aluminum gasket is to allow it to cycle a few times and get real hot, tightening each time after it cools. The aluminum will anneal (get softer) after it it's heated and cooled. Once it's soft, and set it will seal. If not it's an indication of a no flat/rough sealing surface.