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  1. #1
    Jkmike's Avatar
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    Exhaust manifold corrosion.

    Has anyone else seen this level of corrosion on their exhaust manifold?

    What's worse is this is after only one season of riding, well one season of riding since I did some minor porting of the exhaust manifold to go with my ported head. I dont even ride in full saltwater, only brackish. I'm kind of wondering if the manifolds come from the factory with some sort of internal coating that I may have unintentionally removed when I ported it.

    Nonetheless, does anyone know of a decent product for painting the inside of the exhaust manifolds?

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  2. #2
    That thing is done. Donít think there is a coating on it,factory wise.
    I think it may be leaking internally. Normally there would be no water passing through that opening. When you (ported it) you may have penetrated the water jacket causing salt water to enter the exhaust chamber.

  3. #3
    EVN81's Avatar
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    Exhaust manifold corrosion.

    Did you drilled and tapped for an o2 sensor?
    See if you can pressure test the manifold.

  4. #4
    Jkmike's Avatar
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    Yes it is drilled and tapped for an O2 sensor, this was done before I bought the ski though but it looks well done. And when I say ported, its more like cleaned up the casting imperfections. I removed as little material as possible to avoid penetrating the water jacket. I did a quick pressure test on it earlier today where I simply connected the two smaller barb fittings together with a piece of hose and filled it via the larger fitting using a hose nozzle that fit perfectly and allowed me to build up pressure inside and couldn't find any leaks. I will make a setup to do a longer term pressure test and see if I get any different results.

    The corrosion also only goes about an inch and a half into the manifold and is only on the part of the manifold that is solid and doesn't have a water jacket.

  5. #5
    Quote Originally Posted by Jkmike View Post
    Yes it is drilled and tapped for an O2 sensor, this was done before I bought the ski though but it looks well done. And when I say ported, its more like cleaned up the casting imperfections. I removed as little material as possible to avoid penetrating the water jacket. I did a quick pressure test on it earlier today where I simply connected the two smaller barb fittings together with a piece of hose and filled it via the larger fitting using a hose nozzle that fit perfectly and allowed me to build up pressure inside and couldn't find any leaks. I will make a setup to do a longer term pressure test and see if I get any different results.

    The corrosion also only goes about an inch and a half into the manifold and is only on the part of the manifold that is solid and doesn't have a water jacket.
    Do the same thing and pressurize with air. Dunk it in a tub of water and watch for bubbles.

  6. #6
    ptscon's Avatar
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    How hot is your tune? That damage may be from running too lean.

  7. #7
    marcroberts's Avatar
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    Quote Originally Posted by ptscon View Post
    How hot is your tune? That damage may be from running too lean.
    I agree I have 3 manifolds I have melted the ends off with really hot tunes

  8. #8
    Jkmike's Avatar
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    So i am pressure testing it now and all seems to be fine it is holding 70psi of air no problem, tried submerging it as well no bubbles. Im going to let it sit for a while and see if the pressure drops but I don't think it is leaking.

  9. #9
    Jkmike's Avatar
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    As for the tune here is a screenshot of one of my logs. Would yaw say that its is too hot based on this?

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    Last edited by Jkmike; 11-05-2018 at 06:00 PM.

  10. #10
    Jkmike's Avatar
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    Here is a better log. But the more i look at these the more i think yaw might be right.

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