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  1. #1

    New guy to PWC and Forum '99 1200XL rear cylinder replacement advice

    I did some trading, and ended up with a pair of skis. A '98 Seadoo XP and a '99 waverunner 1200XL. The WR was "supposed to run, just needs a battery".
    Fresh battery wouldn't jump it, so I took a peep down plug holes. Rear cylinder looked damaged(oil line pulled from carb), so I pulled head.
    The cylinder and piston are junk, but the rod bearing actually feels pretty good. What is my best option for replacing the single cylinder? The other two look perfect, as does the entire ski. It looks to have been in storage and unused for the last 16 yrs. From what I've read, these have a nickel boron coating that doesn't allow sleeving?Click image for larger version. 

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  2. #2
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    That rust on the crank webs worries me. I would be pulling the motor out and tearing the whole thing down. The last thing you want to do is spend 300- 500 bucks on a piston and cylinder only to have the crank grenade because it has rusty bearings.

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  4. #3
    Happily Self-Employed WFO's Avatar
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    Quote Originally Posted by BryanP View Post
    That rust on the crank webs worries me. I would be pulling the motor out and tearing the whole thing down. The last thing you want to do is spend 300- 500 bucks on a piston and cylinder only to have the crank grenade because it has rusty bearings.
    +1
    that crank is done

  5. #4
    xxx2's Avatar
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    +2 Even if it spins freely, the crank webs have rust on them...that means the bearings do as well even if you can't see it. If you bolt on a new cyl/piston and run it, It may last 1 minute or 1 season before it starts knocking and possibly let loose busting a hole in your cases rendering them to scrap aluminum....where do you think you'll be when that happens. Not worth the risk/reward, Do it right the first time, go completely through it (carbs too) and it should give you another 15+ years of enjoyment.

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  7. #5
    It sat for a couple weeks apart which resulted in a couple drops of water sitting on those spots. There is no other rust on, in, or around engine. Or I would definitely agree with the full rebuild.

  8. #6
    Happily Self-Employed WFO's Avatar
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    The cylinders are nikasil plated. You can sleeve the cylinder, but there is a good reason Yamaha uses nikasil.

    You have 3 guys that glanced at the 1 photo you posted and say they recommend you tear it down and fix that crank, and probably 30 more have viewed it and not posted, but are thinking the same thing.

    Why not listen to the advice of guys that have seen this before?

    Where do you think all that material went that came off the piston? Into the crank bearings. And then add moisture/rust to the mix...

    Do what you like, but just replaceing the cylinder is not a gamble I would take at my shop. Been there, and they always come back worse than when they left. Usually with ventilated cases.

  9. #7
    Happily Self-Employed WFO's Avatar
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    ... and if it sat for as long as you think you should go thru the carbs too

  10. #8
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    Even if those rust spots came from a few drops of water, its obvious in the pics that there is all kinds of crap down inside the case and most likely in the bearings. Best case for you is that you tear it down completely, clean it all up and oil it and everything is fine. Worst case is that you either tear it down, or don't tear it down and the crank fails from either rust or debris. Then you probably have ruined an expensive set of cases and probably a cylinder. There is no way in hell I would ever just try and clean that motor out and try to run it with a new piston. There is way too much junk in the cases.

    I have replaced just a cylinder and piston on one of my machines. I had a plating failure on one cylinder. The case was clean lucky for me. I just wiped it out really well and oiled up everything really well. Still doesn't mean I wasn't nervous riding it for a while. I have probably put 20 hours on it since then, and it has been good.

    These cranks do not like anything at all in them. The slightest bit of rust on a bearing or debris in a bearing can kill them almost instantly. When cranks fail, they take out a lot of stuff with it. Not worth the risk.

  11. #9
    Ski Hacks MG's Avatar
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    Only a fool would not pull and rebuild that mess. Don't be that fool.

  12. #10
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    I know its not the answer you want, but listen to the guys here. Nobody wants to steer you in the wrong direction or see you go that way. Look at the skis in my signature. They are old. They have all been great skis for me and reliable. Why? Because I took the time to build them right and build them once. Your experience will be a lot better and more fun if you take the time and money now up front to go though the whole ski completely from nose to tail and make sure it is all 100% correct. We have all seen this play out in front of us before. We are here to help and make sure you get the best experience you can possibly get.

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