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  1. #1
    quadzilla's Avatar
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    Lightbulb piston wash..???

    Hey there old schoolers....

    Looking for some thoughts on my GP's piston wash at 30hrs....

    Also a bit of an anomaly regarding a missing 5-6 psi compression in #1 hole..??

    OK then the story so far...

    Fully rebuilt motor in Aug 09:.
    ----------------------------
    Pro-X .25 over pistons.
    Group-k ported cylinder.
    Stock head at 130psi (actually 129-130-131 on a snap on gauge when it was built)
    VF reeds (1's or original VF's) Riva reed spacer.
    Lightly ported intake manifold with filled balance channels.
    Ported crank case. (home made effort).
    Riva CDi. (Rev A).
    Pre-mix.
    Stock carbs.. (jetted at 105 low's 1/2 turn out -/+1/8th, 135 hi's 3/4 turn out -/+ 1/8th, 1.5 N/S with gold spring)

    Thoughts on the wash picture's,. then where is my missing 5psi compression..????
    I'm thinking ring end gaps..???

    Oh and even with the lowish pilot jet i still have a slight rich bog out the hole..??
    This is also with no F/A whatsoever fitted at the moment as the bog gets worse with it installed.. (increased signal..???????? )



    Finally:.
    Here is a buddy of mine having his fix.. (his words) the ski really does go quite well..
    Just need to cure the slight bog some more...!!



    Input please guys...???

    Gerry
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  2. #2
    quadzilla's Avatar
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    Oh...

    Meant to say......

    Notice anything unusual about the wash...????

  3. #3
    Mpeavler's Avatar
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    Looks just a shade closer to lean to me...I would want just a tick more wash if it were mine. I'm not saying it's crazy lean....but I would personally go a 1/2 jet richer depending on which phase your testing in terms of wash.

    M

  4. #4
    quadzilla's Avatar
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    Quote Originally Posted by Mpeavler View Post
    Looks just a shade closer to lean to me...I would want just a tick more wash if it were mine. I'm not saying it's crazy lean....but I would personally go a 1/2 jet richer depending on which phase your testing in terms of wash.

    M
    Mike....

    This is after 30hrs of use.. no Abuse is the correct term here...

  5. #5
    Mpeavler's Avatar
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    I would go up slightly in jetting by 1/2 to one jet size....the extra fuel will make it live longer...and would be more in the comfort zone to me....

    That bog...could be lean ..if it's down low...add 1 size up pilot's ....and or lower pop off pressure...

  6. #6
    cheatin' piston popper addicted's Avatar
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    Gerry,

    pic of the cyl on the floor is stock jetting. assembeled engine wash is how I roll. fatty fat but safe.
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