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  1. #1
    Wankel till I die!! jonjonwells's Avatar
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    What would cause backfires????????

    As the question states, I have a ski that is backfiring. When it does it, there is a loud pop out the exhaust and the rubber connecting pipe between the stinger and waterbox flattens out. Any ideas.


  2. #2

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    Timing is out,
    loss of power for a second,
    cut off switch earthing out for a second,
    over fueling
    underfueling,
    faulty stator
    faulty cdi

    unfortunatly there are quite a few causes

    mick

  3. #3
    Wankel till I die!! jonjonwells's Avatar
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    umkay, well that sucks. I was hoping for something easier. Oh well, off to work then.

  4. #4
    ph2ocraft's Avatar
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    jonjon, use a jumper pack and see what happens.

  5. #5
    ph2ocraft's Avatar
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    If it fires off with no more back firing it's the battery.
    The 2nd most common reason for a backfire is a bad stator, test it as outlined in the tech section.

  6. #6
    My backfire was from a out of index crank.

  7. #7
    She likes the bike. But the ski gets her wet!!!! xlint89's Avatar
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    I backfire when I have beans. Backfire out the waterbox is usually rich, is your choke stuck closed by chance?

  8. #8
    Wankel till I die!! jonjonwells's Avatar
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    Nope on the choke. This ski sat with about 8 inches of water in the hull for 3 days. The owner fired it up and somehow it ran like crap (duh). Pulled the plugs, found one of them was smashed, like someone took a hammer to the tip. Also found about an inch of water in the CDI box. Did a full rebuild on the carbs just to make sure there wasn't any mud/water in there (there was).

    Possibilities:

    Crank out of index
    CDI fried
    Stator Fried
    Coils weak
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  9. #9
    SeaLion's Avatar
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    Broken reeds can also cause a backfire or are a result of backfires. Don't forget to check the reeds.

  10. #10
    She likes the bike. But the ski gets her wet!!!! xlint89's Avatar
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    Make sure the carb orifices are completely clean. A little dirt particle can clog it and cause the backfire. Also make sure the elec box is not rusted on the board, including the bottom side.

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