Top end tear down questions
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  1. #1
    PWCToday Newbie
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    Jun 2019
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    Top end tear down questions

    Hey all.
    So I got the sbt cylinder exchange top end kit for my 97 Gtx. I knew little about the ski getting into it other than it didn’t run and I was told it just needed a gasket of some sort...it had 140 hours.

    I received it with the cylinder head and jugs loose..in some state of repair or disassembly. .I had a hard time with some of the manifold bolts and I think the guy tried to rebuild it and gave up when they ran into problems with seized bolts...
    the pistons and plugs look good. I got the cylinders off and realized the pto jug has a 1.5 inch crack in the exterior water jacket. The pistons do not appear to have seized...I did notice a little more oil on the skirt of the mag piston....
    the rods are clean with no obvious extraordinary play...
    i pulled the rave valves and they were pretty dirty. Lots of black buildup and get this..no spring on the side with the cracked cylinder. Coincidence?

    So now I have more questions than answers and wished that I just went with a whole new sbt motor....already out another 50 bucks on an eBay core..

    could they have cracked the cylinder due to overheat without signs of scoring on the cylinder walls? What would cause an inch plus crack on the exterior wall of the jug? Why the hell would the rave valve spring be missing? I guess it is possible that they somehow cracked the jug then attempted a rebuild and just lost the spring as they were disassembling and then putting it back before offloading it on me...

    any thoughts?

    Also, I thought I’d get rave valves with the cylinder exchange but I didn’t. I went stock bore replacement..do I need to trim these things or should the clearances match from factory?

    The head looks clean...should I bother to have it shaved and leveled or just check for level and leave it as is?

    Thanks
    Last edited by Cassious; 06-26-2019 at 01:01 AM.

  2. #2
    Frequent Poster
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    Re: Top end tear down questions

    could have froze , improper winter storage, spring for rave my be laying in the bottom of the hull, most used boats that owners work on themselves have a pile of bolts, nuts ,washers in the back of the hull

  3. #3
    PWCToday.com Is My Home Away From Home Myself's Avatar
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    Re: Top end tear down questions

    I agree. Most likely froze and busted out causing a huge water leak when they tried to run it. Spring is likely inside the hull under the engine. Try putting it nose high and using the water hose to flush it out towards the rear. If it's std bore theres no need to trim the RAVEs. Color the head with a sharpie and rub it around on a piece of 320 wet sandpaper on a flat surface. Any sharpie left after rubbing is a low spot.
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  4. #4
    PWCToday Newbie
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    Re: Top end tear down questions

    Awesome. Thanks.

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