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  1. #1

    951 compression question.

    I have a 2002 RXDI.. has 174 hours on it.. But I don't ride it that hard. Ran fantastic up to the last day of this summer. Just lacked some power.
    Took it to 2 shops.. both said the the compression in each cylinder was 90 psi.. very low for a 951... and that my fuel pump was not putting out the pressure it should.. ( I just had a High Flow installed mid summer and I figured that was the issue ) . ** It also had a low battery around the time it was at the shops. **

    To make a long story short, I replaced the high flow with the New upgraded version High Flow ( because it has a lifetime warranty ).. took it out and it ran great .. even with the 90 psi. I had it up to 52 mph with choppy water. ( Top speed I usually got was 56-58 on glass ). Im actually heading back out on New Years for another test.

    Could the low battery have the Psi come up low on the gauge ?

    One of the techs said the pistons looked to be in great shape.

  2. #2

    Join Date
    Aug 2008
    Eastern NC
    Yes. You should have the battery fully charged when doing a compression test.

  3. #3
    wotxxxsd's Avatar
    Join Date
    May 2012
    Get a compression guage and check it yourself. They are @$40 at the auto parts store.
    Yes low battery can reflect low compression #s

  4. #4
    Myself's Avatar
    Join Date
    May 2007
    North Central Arkansas
    Need fast cranking speed for true compression reading. Could be a bad gauge also.There's no way that thing would be doing 52 in chop with 90psi.

  5. #5
    wkuadam07's Avatar
    Join Date
    Feb 2013
    Bowling Green, KY
    I would never START in the water with 90 psi on both cylinders... there is some other problem...

  6. #6
    Just did a new compression test with a brand new battery ( used two different gauges ) .. came out at 120 per cylinder.. so the low battery did show 30 psi less. Took it out on New Years Day and it ran great.. had it up to 56 mph several times. Im sure 120 is still lower then it should be .. but its running great.

    Click image for larger version. 

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  7. #7
    ncdoo's Avatar
    Join Date
    Nov 2007
    Eastern NC
    120 is good. Run it.

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