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  1. #1
    spud's Avatar
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    XLT Carb Insulator?????????????

    Why do the XLT's have an insulator between the mainfold and the reed cover plate? Is it neccessary? I am repairing a ski and noticed the insulator. At first I thought it was some type of performance mod so I checked the parts finder and there it was?

    Hopefully some XLT guys can chime in. The ski has a D-Plate so cat heat will not be an issue.


  2. #2
    Moderator OsideBill's Avatar
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    I had one of these on the 01 GPR I bought. I left it on, only reason was the bolts would not fit with it removed when using the stock reed cages. It is an extra gasket to worry about in my opinion.

  3. #3
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    I look at it as another area for failure as well.

    The head and one cylinder are toast. The rings didn't spin. There is no water ingestion. The cylinder had lubrication. I am suspicious of that frickin insulator. They used paper gaskets to put it in. What gaskets did you use Bill? I can't believe paper is OEM. The Yamaha gaskets I am used to seeing are steel with teflon or foam rubber on them. I think it went lean due to leakage around that gasket. It looks like the ski was run for a little while after the first failure making it harder to diagnose.

    The carb rack comes off tomorrow. Hopefully the villan will be exposed. I always feel better after root cause has been established.
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  4. #4
    spud's Avatar
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    Note the bit of detonation in the domes on #2 and #3. #3 was probably on the verge. The pin was starting to back out in the power valve.

    So looking at good cylinder, good head , wave-eater clips, RPM couplers (you should have seen the slop the number 1 power valve hardly moved at all), new crank, 3 new piston assemblies 2 for #8 cylinders all new gaskets and seals. Then rejet and F/A's with outerwears. That should put a smile on her face.

  5. #5
    Moderator OsideBill's Avatar
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    Quote Originally Posted by spud View Post
    I look at it as another area for failure as well.

    The head and one cylinder are toast. The rings didn't spin. There is no water ingestion. The cylinder had lubrication. I am suspicious of that frickin insulator. They used paper gaskets to put it in. What gaskets did you use Bill? I can't believe paper is OEM. The Yamaha gaskets I am used to seeing are steel with teflon or foam rubber on them. I think it went lean due to leakage around that gasket. It looks like the ski was run for a little while after the first failure making it harder to diagnose.

    The carb rack comes off tomorrow. Hopefully the villan will be exposed. I always feel better after root cause has been established.
    I bought new OEM gaskets one was the newer rubber type ones and the other was the Foam covered metal one. I have a couple more in my box if you need them.

  6. #6
    spud's Avatar
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    All three high speed screws were set at 1 1/4. With stock jetting that sounds low. What does Yamaha set them at before putting the tamper caps in?

    Still no smoking gun. I'll probably find it tomorrow night.

    Stay tuned and offer any advise.

    Thanks

  7. #7
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    I checked the part numbers and the gaskets that go with the insulator are different than the gasket we use for the GPR. I still don't know if the gasket material is paper or like the GPR gaskets. I know the ski has paper gaskets in it with no sealant.

    Bill,

    Did you go to the XLT area and buy the gaskets specified for the insulator?
    Last edited by spud; 09-18-2007 at 07:47 AM.

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