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  1. #1
    Nothing like getting air, while sitting in a chair VonnerNIX's Avatar
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    '97 GP1200 Cyl #2 has 0 psi

    I just bought a 97 GP1200 and the previous owner, my dad's previous boss whom I bought another ski off of 7 years ago, indicated he hadn't run it in a few years. Because of this relationship I did not run a compression test on the cylinders. It did fire up and sounded like it ran great. I did notice there was some oil in the hull, but related that to poor upkeep and sitting idle for 2 years (never had to work on a ski with problems before, my 93 700 vxr pro has worked flawlessly). I took it to the lake last week for a family reunion (first time running it). It worked partially for 1 day then crapped out. One of the main reasons I bought it so we could use it at the reunion for family to ride and enjoy, but since that didn't work out so well... now I am interested in getting the thing fixed so I can at least ride it again this season.

    I tested compression on all cylinders and found that #2 had 0 psi. #1 and #3 had approx 100psi. I was confused and concerned because everything I have read was related to #3. However, as I started to take the head off I noticed that the oil line for #2 had become disconnected from the pump (which explains the oil in the hull now). So that is my thought at the failure.

    I am very mechanically inclined, but have never performed work on any type of engine. I am excited to work on this project and get this thing running again (even though it's going to take a lot of time and money).

    You can find pictures of the current status/progress below
    97YamahaGP120002

    Based on these pics can anyone help me figure out what needs to be replaced?

    I am also planning on rebuilding the carbs, installing primer & removing choke, possibly going pre-mix. I have read about the D plate & chip, but am unsure what this does/gains. Any other simple mods? At this point I don't need anything crazy, it is going to be a family ski, so I don't need crazy performance, just reliability.

    Well I think I have rambled long enough, and hope to get some responses to help me through this.

    This is the thread that inspired me to join the forums after talking to lagernuts through email briefly.
    http://www.greenhulk.net/forums/show...-line-fell-off
    Last edited by VonnerNIX; 07-18-2010 at 10:52 PM. Reason: Added email notification


  2. #2

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    Stardard yamaha oil line failure- the zip ties on the oil lines have no way of coping with the natural shrinkage/ stretch of the factory oil lines as they age. Although I can't access your Picasa album for some reason, you'll most likely need an oversize piston and ring set, and your center cylinder bored and honed for your new piston. While you're at it, check Island Racing for a new oil line kit; it'll save your other two cylinders.

    -Mateo

  3. #3
    Nothing like getting air, while sitting in a chair VonnerNIX's Avatar
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    I am not sure why you can't see picasa album...It is listed as a public album. Below is a pic of the cylinder and piston.



    Edit: I can't figure out how to remove the attachment, since I linked directly to the pic.
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

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  4. #4
    Nothing like getting air, while sitting in a chair VonnerNIX's Avatar
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    Does anyone know of a reputable shop in St. Louis that would be able to do this work? Also, what parts would I need to buy to repair this? Sorry for the ignorance, but I have no clue, an want to make sure I get the proper parts the first time so I can hook it all back up.

    Also, do I need to do anything to the other 2 cylinders, or is just the middle one okay to fix?

  5. #5
    Nothing like getting air, while sitting in a chair VonnerNIX's Avatar
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    I found a good machine shop who is going to do the boring, but they need me to buy the pistons before they bore it to size.

    Should I get WSM Platimum or Pro-X oversized? Also, I would rather not bore all 3 for money reasons, but will that cause me problems in the future? If it is better to do it now, I will bite the bullet, but if it doesn't have to be done I will just play it out and see how it goes with only boring 1.

  6. #6
    Moderator OsideBill's Avatar
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    Pro-X is a better piston. You can get away with just boring one, but it is recommended to keep the rotating mass equal so boring them all will make a better running machine.

  7. #7
    Nothing like getting air, while sitting in a chair VonnerNIX's Avatar
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    Thanks Bill. Let me ask this, would it be better to overbore to 85mm instead of 84.25? What would that gain me if I was going to bore all 3 anyway, is bigger bore considered better?

  8. #8
    Moderator OsideBill's Avatar
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    not really in this case, I would go minimum possible and leave room for the future. 84.5 is pretty common size of available pistons on the aftermarket, if it were me that's where I would go.

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