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  1. #1

    Smile Mystery is solved!!

    well the sltx that had ingested water and had 2 tight spots where the crank was binding ,leading me to think it was out of index.Guess what I had pulled the center cylinder and the piston skirt was broken off about a 50 cent piece size.the cylinder had no damage and the piece was no where to be found.I figured since when rolling crank by hand it would bind at 2 spots 180deg. from each other ,very smooth otherwise.That the crank had been knocked out of index causing it to bind.Well today got engine out ,pulled other 2 cylinders and found what was causing binding,the L-rings had so much carbon built up behind them,and were locked in groove.CRankshaft is perfect.What could have caused this build up.Cheap oil from previous owner or perhaps first owner used twc oil and current owner using quality tcw3??The flame pattern indicates they were running slightly lean,not enough to be the cause of problem.I am going back with a set of forged pistons ,I was hoping wiseco offered a set with td rings however they only offer LF-rings.So anyone have any problems running wiseco in 1050 engine??WEll just wanted to let you guys know the water didnt hurt crankshaft and I was barking up wrong other question if the water pressure used to flush PWC after a salt H2O ride is over 85psi could it cause water to be forced back into cylinders from pipe???Or could his using extra oil in fuel (he mixes at 75 to 1)plus the oil pump have caused the ring problem???I thought the newer high quality TCW3 oils actually kept carbon from building up,not caused it.Like I said this problem was from first owner as front cylinder was down 15psi from other when he bought it,and he put over 900 miles or more on ski ,plus 23 hrs.(he rides 100mile round trip loops in gulf)thanks>Marvin

  2. #2
    Click avatar for tech links/info, donation request K447's Avatar
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    Jul 2007
    near Toronto, Canada
    My understanding of the variable rate oil pump is that it flows about 100:1 near idle, and about 40:1 (32:1? ) at WOT. I don't know what the flow curve is between those two.

    Wouldn't 75:1 oil in the tank, plus the normal oil pump flow (if the oil pump arm was set to spec), result in roughly 50% more or possibly twice the normal oil rates through the engine at mid-range speeds?

    I would think using a good synthetic 2-stroke oil going forward would help keep the carbon build up in check. And the extra lubrication of synthetic should allow the owner to forgo adding oil to the gasoline, or at least go much thinner.

    BTW, before or after his long rides, does this owner have an extended idle period (say through a long no-wake zone)?

    Regarding water pressure during reverse flushing, there is a pressure drop at the adapter to the water manifold, and a pressure drop through the length of the garden hose.

    The reverse flushing connection means the water jacket is open to the outside via the jet pump cooling water inlet. And if the pressure does get a little high in the water manifold, it should open the pop-off valve in the thermostat housing, further relieving water jacket pressure. Combined, I wouldn't think the actual water pressure in the engine water jacket is all that high.

    Does anyone know how high the cooling water pressure from the jet pump gets when these machines are running WOT on the water?

    As long as the engine is running, there should not be water flow backwards through the exhaust.

  3. #3


    my sentiments exactly ,he flushes it correctly, engine on water on ,water off rev engine engine off.yet there was slight sand and h20 in both other cylinders .i didnt pull them until engine was out, and i left head bolted up to prevent water or junk from going in cylinder, it was already there as it was rusty,and damp.soft rusty goop. the carbon was hard as nails,no he idles for about 3 minutes while warming up engine in no wake zone. uses merc. premium tcw3 from merc. racing ,pretty awsome oil. i have used it in kawasakis for 20 yrs. both in hard rental use and in racing,never had oil related failure with it before, i know the compression was down when he bought it,15psi less at cranking, but he said it ran fine ,.i am really suprised i cant find missing piece of piston,OH the rusty water came from when it died he never flushed it or started it again,I just found that out.I thought he had flushed it.But the piece of piston is missing ,no marks on it or cylinder or head,could he have been so lucky it went up transfer ports out exhaust without touching anything,out of hundreds 600+ last count rebuilds this is a first for me,no marks,scratches,dings,just a missing piece of piston,I thought it would have caught in crankcase nope he was running flat out,it bobbled quit.and never been started since>Marvin

  4. #4
    Click avatar for tech links/info, donation request K447's Avatar
    Join Date
    Jul 2007
    near Toronto, Canada
    Quote Originally Posted by mrjetskey View Post
    ...I am really surprised I can't find missing piece of piston...
    Have you looked in the water box?

  5. #5
    If he's mixing gas already why not disable the oil pump and just run mixed gas? It's always the right ratio and if you're already mixing why not? On my pro I have the oil pump there but have the rod disconnected and tied down so it's at the idle amount all the time. It does load up a bit if you idle for a long time, but I left it like that just because it's easy to hook back up if I want to.

  6. #6
    I've seen skirts break without causing any damage what so ever. I've also seen them break cases, wreck cyliders and more. I guess he was a lucky one.

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