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  1. #181
    www.eastcoastpwc.net Scott's Avatar
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    Quote Originally Posted by LindenPWC View Post
    mine is cracked there and no loss of power? how did you fix your head?
    I ended up replacing to play it safe


  2. #182
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    Apologies for resurrecting this thread but several questions have come to mind that I'd like to hash out without starting another thread. It has been mentioned before in this thread that the head cracking issue is likely due to thermal stress. It also sounds like even the new castings were having some issues on the older blocks. I am curious though whether or not the cooling check valve that was added in the 10' models actually helped this issue. Perhaps the check valve in combination with the revised casting? The check valve restricts flow at higher rpm which would keep water in the head longer during higher rpm and wot runs. This would seem to minimize the shock of relatively cold water hitting a hot head and causing thermal stress. Also, it would be good to know what the water temps were in each of these cracked head situations. My 08 250X doesn't seem to have any head issues but the water temps here are always in the mid 80's year round. Finally, I was wondering if the extra cooling jackets couldn't just be blocked off with some JB weld. Call me old school, but myself and many others have used this technique while fitting newer jeep 4.0 heads on old amc 4.2 blocks. We would block several of the ports with JB weld and never had any issues. Granted, those were cast iron heads. Just my $.02

  3. #183
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    Just re-read the whole thread and found what I was looking for. Seems this theory is likely the culprit. I'm going to reroute the cooling lines going to the head. Pump>magneto cover>head & Pump>oil cooler>head. That should help "pre-heat" the water a bit and help with the thermal shock. Also going to make sure to do the "cool down" runs before shutting it off.

  4. #184
    Hi 2 All especially the Aussies on this forum. My Ultra 250X 2007 161 Hours Original Head.It is Cracked between 2 and 3 cylinder.
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  5. #185
    Take the time to smile sirbreaksalot's Avatar
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    [QUOTE=Kwacka2FiddyX;3053705]Hi 2 All especially the Aussies on this forum. My Ultra 250X 2007 161 Hours Original Head.It is Cracked between 2 and 3 cylinder.[/QUOT
    Its dead fred ......

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