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  1. #1
    Formerly Ultra250 TN Aquaholic6801's Avatar
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    Pulley Kit Question

    Ok I know everybody is blocking off the BOV, its my understanding that the BOV is the secondary safety relief for the supercharger. Am I correct for thinking that?

    And the other is vaccum assited and is the primary relief valve?

    If putting on the pulley kit ups the boost, what is to be done to the primary relief vavle to keep it from releasing the added boost?


  2. #2

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    nothing, the line from the manifold will keep the valve closed. It provides positive pressure on top of a diaphram to hold the valve closed under boost. When the throttle is closed it becomes less postive/vacuum and the pressure from the sc will open the valve to relieve pressure.

    Provided the spring and diaphram are in good shape it should be fine
    Last edited by spaulding; 10-27-2007 at 01:33 PM.

  3. #3
    Silence! I Keel You! earthshaker's Avatar
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    Quote Originally Posted by Ultra250 Tn View Post
    Ok I know everybody is blocking off the BOV, its my understanding that the BOV is the secondary safety relief for the supercharger. Am I correct for thinking that?
    Yes, your thinking is correct. According to the SM, your BOV should not open before ~26 psi (185 Kpa converted), so technically, you should not need to block it off by increasing the advertised 11psi boost by a couple of pounds, however we all know that the BOV's are opening anywhere between 2 - 8 PSI....at least the ones i have tested. By blocking your BOV you are now relying 100% on the relief to which some folks have had the line pop off.

    The manual may be wrong but is all i have to go by unless Kawi replaces that page in my service manual. It seems logical to me that the BOV should begin to leak at around 12PSI or so stock.

    I have spent a decent amount of time with my dealer communicating to Kawasaki and this is clearly not on their priority list. I've been very calm and professional and not called or emailed Kawi direct. They are more interested in the performance of my ski rather than addressing the very simple plain out fact that my BOV blows before spec (which is a performance loss that will vary from ski to ski). I could squeeze harder but am picking my battles.

    Kawi did send two brand new valves that i tested and they blew slightly earlier than the ones we have on the skis! They would not approve us to adjust the stock valves either.

    So to gain the most performance from the pulley kit, your BOV will likely have to be addressed and set higher than the kit can produce or take the risk and block it. Many here have blocked and have indicated no problems....I say YET. If you send me your BOV like you were going to do earlier, my offer still stands to test and adjust for you if you'd like.
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  4. #4
    Great info. Can you help with these?

    1) Is there an alternate more reliable blow off valve?

    2) How often should BOVs be replaced for normal wear & tear?

    3) Is main symptom of leaky BOV failure to develop more than 5 to 8 lbs of boost?

    4) EShkr, if you re-adjust a leaky BOV, does it then work correctly?

    Thanks.

  5. #5
    Formerly Ultra250 TN Aquaholic6801's Avatar
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    Quote Originally Posted by earthshaker View Post
    Yes, your thinking is correct. According to the SM, your BOV should not open before ~26 psi (185 Kpa converted), so technically, you should not need to block it off by increasing the advertised 11psi boost by a couple of pounds, however we all know that the BOV's are opening anywhere between 2 - 8 PSI....at least the ones i have tested. By blocking your BOV you are now relying 100% on the relief to which some folks have had the line pop off.

    The manual may be wrong but is all i have to go by unless Kawi replaces that page in my service manual. It seems logical to me that the BOV should begin to leak at around 12PSI or so stock.

    I have spent a decent amount of time with my dealer communicating to Kawasaki and this is clearly not on their priority list. I've been very calm and professional and not called or emailed Kawi direct. They are more interested in the performance of my ski rather than addressing the very simple plain out fact that my BOV blows before spec (which is a performance loss that will vary from ski to ski). I could squeeze harder but am picking my battles.

    Kawi did send two brand new valves that i tested and they blew slightly earlier than the ones we have on the skis! They would not approve us to adjust the stock valves either.

    So to gain the most performance from the pulley kit, your BOV will likely have to be addressed and set higher than the kit can produce or take the risk and block it. Many here have blocked and have indicated no problems....I say YET. If you send me your BOV like you were going to do earlier, my offer still stands to test and adjust for you if you'd like.
    Now that I am done riding it for the year, I may send you both of them that I have, I have a stock unadjusted and one that I have adjusted.just need to get the 250 on a single trailer so I can get in my garage to work on it.

  6. #6
    shhr's Avatar
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    I knew you could not wait very long, just get the kit it is only money

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