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  1. #1

    Yam 2 cylinder hours VS compression?

    Just curious what ya'll think about this...I have a recently acquired 800xl with @ 235 hours on it...I just checked compression and its dead on at 123 each cylinder! I was obviously quite happy about this but was wondering if this is possible and/or normal? You think gauge has been changed, top end rebuilt or just normal? Thanks for replies!

  2. #2
    I have a 2004 xlt 800 with around 180 hours and it's at 134 and 135. Only thing I've done is upgrade the power valves after first 25 or so hours.

  3. #3
    oh, ok thanks...I thought stock was 120-125 ish did the valves raise compression? how much?

  4. #4
    120 stock......with a good gauge. 235 I would do a top end just for insurance purposes. Cheaper to do it now vs it blowing up and having to renick a cylinder. Wouldn't be more than a couple of hundred dollars Pro X makes a nice set that I have used in the past comes with the rings I believe too. SO just need a set of gaskets and wrist pin bearings

  5. #5
    Power valves will get it first. I would change them out ASAP unless you can prove they have been recently replaced/upgraded.

  6. #6
    Myself's Avatar
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    May 2007
    North Central Arkansas
    I just tore down an 800 this weekend with a bad lower rod bearing thrust washer. The front piston looked nice except for a few small aluminum shavings sitting on top. The power valve has a nice newly cut edge to it and was just about to fall into the cylinder when the thrust washer came apart and locked up the crank.

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