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  1. #1
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    Unhappy Compression test, are the #'s weird here???

    I have a 2004 GP1300R Riva stage 2 and some fourm ideas done to craft also. I did a compression test yesterday and these are my #'s.
    Elevation: 1215ft.
    Cylinder #1: 140lbs.
    Cylinder #2: 140lbs.
    Cylinder #3: 130lbs. (this is the one I'm concerned about, should I be)???

    Riva Yamaha posted the compression #'s to be 145-150lbs for all 3 cylinders. Or is this just another one of their sales lies Are these compression #'s look about right. I'm not sure on in this type of thing.

    Also, what can I do to get alittle bit more compression out of my engine. If I can, how do I go about doing it???


  2. #2
    Mr Bill's Avatar
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    #3 is typically lower than #1 and #2. Looks to be ok in my book, but I am sure someone will verify.

  3. #3
    Hydrotoys's Avatar
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    Its fine.

    Maybe you should go ask those folks at Riva about it.

    http://rivaforums.com/eve/forums?a=t...664#4801030664

  4. #4
    Happily Self-Employed WFO's Avatar
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    Quote Originally Posted by GP1300R powerhouse View Post
    I have a 2004 GP1300R Riva stage 2 and some fourm ideas done to craft also. I did a compression test yesterday and these are my #'s.
    Elevation: 1215ft.
    Cylinder #1: 140lbs.
    Cylinder #2: 140lbs.
    Cylinder #3: 130lbs. (this is the one I'm concerned about, should I be)???

    Riva Yamaha posted the compression #'s to be 145-150lbs for all 3 cylinders. Or is this just another one of their sales lies Are these compression #'s look about right. I'm not sure on in this type of thing.

    Also, what can I do to get alittle bit more compression out of my engine. If I can, how do I go about doing it???
    Yamaha designed their OEM heads to yield lower compression on #3 cylinder. If you are using Riva 45cc heads, they should be the same across the board.

    And a FYI, you have 15% less air for every 1000' in elevation.

  5. #5
    mrbtd's Avatar
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    Quote Originally Posted by Hydrotoys View Post
    Its fine.

    Maybe you should go ask those folks at Riva about it.

    http://rivaforums.com/eve/forums?a=t...664#4801030664

  6. #6
    Moderator RX951's Avatar
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    Quote Originally Posted by Hydrotoys View Post
    Its fine.

    Maybe you should go ask those folks at Riva about it.

    http://rivaforums.com/eve/forums?a=t...664#4801030664


  7. #7
    WATER WOODY's Avatar
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    Quote Originally Posted by WFO View Post
    Yamaha designed their OEM heads to yield lower compression on #3 cylinder. If you are using Riva 45cc heads, they should be the same across the board.

    And a FYI, you have 15% less air for every 1000' in elevation.
    Its 8-9 psi every 1000' you go up.

  8. #8
    Moderator RX951's Avatar
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    Quote Originally Posted by WATER WOODY View Post
    Its 8-9 psi every 1000' you go up.
    I'll have to remember that. Good info

  9. #9
    WATER WOODY's Avatar
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    And.....its 3% loss in air density every 1000' you go up.Mine loss is 12% up here!!!!!!!!!!! On a 225hp motor,im getting(average) a 27hp loss !!!!!!!.... Another 27hp should give me 3.5-4 mph gain!

  10. #10
    Me Hahn and Joe H204YOU's Avatar
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    Quote Originally Posted by Hydrotoys View Post
    Its fine.

    Maybe you should go ask those folks at Riva about it.

    http://rivaforums.com/eve/forums?a=t...664#4801030664
    I heard they give grate advise too

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