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  1. #1

    XL 1200 leak down question

    I did a leak down test on my 99 xl 1200 ltd. Is it supposed to leak accross the case in these skis? and by that I mean, if I pressurize the bottom of the #3 cylinder, should it go into the bottom of #2 and #1? I had to block off all 3 intakes and exhaust ports before it would hold pressure. Does this sound right? To me I dont feel like it should do this because if there is pressure in the bottom of one to force the gas up into the cylinder, it would leak accross to the other cylinders that have a vaccum trying to pull fuel from the carbs. but I could be wrong. Any help is appreciated


  2. #2
    Happily Self-Employed WFO's Avatar
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    yes thats normal

    each cylinder is independent, but the exhaust is not

    only thing that really ties them all together is the exh mani and balance plate on the intake side

  3. #3
    dockwalker's Avatar
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    You have to plug all holes including exhaust.You're checking for leaks that will cause it to run lean and seize.If it does not hold 10lbs for 10 minutes, spray with soapy water to find leak.

  4. #4
    Thanks guys I found the answer to my question also. Just so any one else who wants to know. Yes, these skis will leak accross the case because each section is seperated by a "Labyrinth seal" which are not made to hold pressure indefinitely, but rather to regulate the amount of air that can escape through them in a period of time. So, as each section changes from pressure to vacuum thousands of time per minute, these labyrinth seals do not let enough air escape to matter. However, when pressurizing the case, these will leak. So you need to block off all ports to do the test, not just one cylinder.

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