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  1. #1

    Ultra 250x Rebuild questions

    Hi guys,

    I started a thread in this regarding my ski seemingly running on 3 cylinders, it seems #4 is working but is only at 50psi.

    My thread got moved to FAQ's but at risk of losing a large audience of knowledge base I thought I would post my findings and questions in this section to reach as many as possible for direction.

    See below:







    Ok lads,

    Judgement day has come, my compression tester and bore scope came in the mail yesterday.

    Unfortunately judgement day wasn't kind and now I'm in need of some serious direction.

    I could see bugger all with the bore scope however the compression test told me all I need to know...

    125, 125, 125, 50

    Managed to get 75 out of #4 with a wet test.

    It doesn't seem to be causing any adverse effects yet but that said if it happened on my last run I haven't been out since so who knows, if I was to put it through its paces now it may spit oil at me from various outlets.

    Now, moving forward any assistance and direction is greatly appreciated:
    1) What's the cheapest I can repair this assuming I've doing the work myself, am I able to simple by a top end rebuild kit similar to the link below and simply dismantle, hone, install parts and voila or should I be doing other things to ensure reliability?

    2) Can I go higher compression forged pistons on stock management and fuel system to set me up for a little more boost down the track without it running off or having problems whilst still on stock bolt ons / electrics?

    http://www.ebay.com.au/itm/Kawasaki-1500-Ultra-250X-2007-2008-Top-End-Rebuild-Kit-010-846-10P-13001-3738-/122100675151?hash=item1c6dc4724f:g:0HQAAOSwT6pV1ax D


    Ideally I want to replace ONLY what is needed to make this run reliably as opposed to doing a complete rebuild given it seems #4 is fubar a piston and ring set should be all correct? However I'm not opposed to forged pistons so I can increase boost and fuel down the track and to be honest am half inclined to go this way.

    Does anyone have an idea on minimum cost this exercise is going to set me back? It's summer here and I want to get the ball rolling.

    Thanks in advance!
    Last edited by skeletonbobo; 11-05-2016 at 03:25 AM.


  2. #2

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    Rings/piston 150ish a hole, maybe more i cant remember but rings are expensive!

    Head gasket 130

    Lap the valves back in yourself plus valve stem seals 40

    Misc exhaust gaskets 40

    Not too bad but you cant just hone out the cylinder if it's all scraped up. Its nikisil coated. Soooo if its that bad you'll have to have it honed and replated. Not sure the cost of the hone job but replating is about 100 per hole. If you do all 4 holes plus honing you're typically better off finding a used cylinder. 400+ is usually fair.

    That kit you linked to isnt a bad price assuming the parts are good quality.

    Hope that helps a little

  3. #3

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    Your motor likely has one of two problems:

    Valves not seating properly. An easy and fairly inexpensive repair... just replace and/or lap the affected valves. One test I use to check the seal on the valves is to spray fogging oil into the head on top of the valves. If the oil drips through, the valves probably need attention.

    or

    Rings stuck in the pistons. This is a common problem on the 4-stroke motors. Just look on ebay at all of the used pistons for sale. A good number of them have rings that are stuck. With the head off, try sliding a piece of coated paper (like from a glossy magazine page) between the piston and the cylinder. If you can slide the paper more than 1/4-inch down, the rings are probably stuck in the piston. You'll need to replace the piston and rings, as it's almost impossible to free the rings.

  4. #4
    Thanks for the help guys.

    It will be bottom end not head related due to pulling 50PSI dry then getting 50% more at 75PSI wet. With an increase of that much between dry and wet that's a pretty good indicator I've got a bad piston or rings.

    Providing the bore isn't grooved to the sh!t would that link more or less have everything I need for the job (less specialty tools of course)?

    I've freshened up cars doing only a hone and rings whilst the motor was still bolted in the car with success on a number of occasions but I'm not very experiences with PWC's.

    Thanks again!
    Last edited by skeletonbobo; 11-06-2016 at 10:20 PM.

  5. #5
    Fat Man, Little Boat Region8Ultra250X's Avatar
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    playing devils advocate here..... has the pump been upgraded?

  6. #6
    Take the time to smile sirbreaksalot's Avatar
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    Quote Originally Posted by skeletonbobo View Post
    Thanks for the help guys.

    It will be bottom end not head related due to pulling 50PSI dry then getting 50% more at 75PSI wet. With an increase of that much between dry and wet that's a pretty good indicator I've got a bad piston or rings.

    Providing the bore isn't grooved to the sh!t would that link more or less have everything I need for the job (less specialty tools of course)?

    I've freshened up cars doing only a hone and rings whilst the motor was still bolted in the car with success on a number of occasions but I'm not very experiences with PWC's.

    Thanks again!
    % of change wet and dry means NOTHING realy, what 1stly needs to be determined is WHERE is the leak down escaping too,
    this is a VERY EASY thing to 100% detect
    and a COMPRESSION test WILL NOT tell the FULL story

    you NEED to perform a LEAK DOWN test.

    1. Sump = Piston/rings/bore condition etc
    2.inlet manifold = inlet valves
    3.exhaust outlet= exhaust valves
    to assume the wet gains you got is your bottom end only with out verifying audible proof is only a guess

    Regards,
    witth out

  7. #7
    Ok, thanks for the advice, I've ordered a leak down tester and will run that once I have it.

    Unsure regarding the pump, upgrade to what and what is the purpose of the upgrade?

    Thanks.

  8. #8
    Fat Man, Little Boat Region8Ultra250X's Avatar
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    Quote Originally Posted by skeletonbobo View Post
    Ok, thanks for the advice, I've ordered a leak down tester and will run that once I have it.

    Unsure regarding the pump, upgrade to what and what is the purpose of the upgrade?

    Thanks.
    search ultra pump upgrade here on the site. plenty of information on here regarding the why for upgrading and the how on how to do it.

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