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  1. #1

    Help Diagnose Piston Seizure

    I bought this 1999 Yamaha XL1200 Ltd used from a guy of Craigslist. He had already started taking it apart to determine what was wrong with it. Found #3 piston was seized and did not want to put anymore money into it. I got it for $800 and figured I could fix it up. Only mods are the D-plate.

    I have already purchased a used cylinder and piston that are in good condition and a rebuild kit for the carbs. Waveeater clips and new oil lines/clamps are on their way.

    Questions:
    Looking at the pictures, can you help me determine if it was an air/fuel problem or an oil issue. There was probably a 1/2 quart of oil in the engine bay and the area under the battery. I could not tell if an oil line came loose, because he had already removed the carbs.

    No compression numbers because the head was already off. Can I test compression without putting the carbs back on?

    I noticed the tamper caps on the carbs are still intact. Do I need to mess with the stock settings for high/low? Can I just rebuild them and bolt it back on?

    Just wanting a ski that runs for the summer. I will do additional mods as I get more cash. Thanks in advance for your help. I've been reading this forum for weeks now trying to soak in as much info as possible.
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  2. #2

    oil lines on this model are terrible

    I just bought a used 1999 XLL 1200 from our local dealer, I decided to go thru the motor for a quick check and glad I did. The oil lines at the carb were just barely on it, you could just pull them off with no resistance. The brass barbs on carbs are just too little to grab the oil lines and the lines must get softer with time as well. Plus they only use a zip tie to hold them, they are too critical to the motor, yamaha should have used something else. Well I replaced the oil lines and used two small zip ties that I got on there very tight. I checked and you can not pull them off, the second ziptie adds alot of security. I like the oil injection for a family ski and they have worked well for years but this seems to be a common problem with all of them. I suspect this is what happen to your ski with the oil you mentioned in the bottom of ski.

  3. #3
    Moderator OsideBill's Avatar
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    In the picture of the carb, the oil line is not connected on #3 this is a common problem. Also what does the power valve look like in #3 cylinder?

  4. #4

    Power valve

    I'm glad you asked about the Power Valve...I opened it up and it was covered in gunk. When I cleaned it all off I noticed it looked different than the one in the used cylinder/piston combo I purchased. The used one did not have the notch in the spacer and top corner was not "cut" off. Here is a pic. Not sure if it is stock or aftermarket. Any ideas? Do I still need Waveeater clips with this one?

    I ordered new oil and fuel lines. I'm gonna use these things called "herbie" clips to attach them. They are used for lines/hoses on airplanes....they are better than a zip tie.
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  5. #5

    oil line clips are big improvement

    finally a really good idea on the oil line failure problem, congratulations on finding these clips, let me know how well they hold, do like I did, put them to the test and tug on them for a good check.

  6. #6
    All hail the Chief! fullboogie's Avatar
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    Been using those clips for about a year on all my fuel lines and pulse lines, and so far so good. You can get them from McMaster Carr - search their site for "snap grip clamp".

  7. #7
    Just a THANK YOU to this forum for providing a invaluable resource for a newbie like myself. I was able to replace a blown piston/cylinder, rebuild the carbs, install waveeater clips, cleaned the powervalves, replace oil lines/clamps and get the ski back on the water. Not bad for someone who has never owned a waverunner before. The biggest hassle was getting the stinger back in! A video of someone taking that thing out and putting it back in would have been helpful. She runs great...only thing I had to do was adjust the idle speed. Last two questions...where does the other end of that vent hose that comes out under the seat supposed to go? What are the two small bolts (look like grounding screws) on the head for?

  8. #8
    quadzilla's Avatar
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    Smile

    Good job on the rebuild rysurio....

    The two items you are referring to are..

    1/. the vent hose will almost certainly be from the battery..

    2/. the small grounding bolts,. are just that..!
    ..... there's a small metal ground lead that goes from the stator cover to the head..
    You will likely need to fish around with a mirror to see it now with the full exhaust back in place..

    And YES you need to make sure its fitted..

    Again good job so far..

    Gerry

  9. #9
    I got the ground from the strator cover and the hose from the battery connected already. I attached a pic of the two items I'm not sure about (since the ski was dismantled when I bought it) and I can't find these things in the manual.
    I'm just guessing that the big vent hose goes down into the engine compartment, since that's the only place it would fit...not really sure what the purpose of that would be? I can't find any leads to connect to the two "grounding screws" and I notice that aftermarket heads do not have those screws. Am I missing something?
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  10. #10
    Happily Self-Employed WFO's Avatar
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    Quote Originally Posted by rysurio View Post
    I got the ground from the strator cover and the hose from the battery connected already. I attached a pic of the two items I'm not sure about (since the ski was dismantled when I bought it) and I can't find these things in the manual.
    I'm just guessing that the big vent hose goes down into the engine compartment, since that's the only place it would fit...not really sure what the purpose of that would be? I can't find any leads to connect to the two "grounding screws" and I notice that aftermarket heads do not have those screws. Am I missing something?
    that hose just goes down to the bottom of the hull for ventilation

    never seen those screws on a 66v before

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