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  1. #1
    Joe Stang's Avatar
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    185 psi too much on each cylinder for pump gas?

    Did a quick check on of compression on my 800 engine, came up with 185 on each cylinder.

    im always running 93 octane in it with some oil, should i put my stock head back on?? I have an r&d rec head on it. Thanks in advance.


  2. #2
    This is too much for pump gas. I run 165psi in my Pro 785 and mix 93 octane with race gas. I ran 185psi in my 96 XP when I had it and ran striclty race gas.

  3. #3
    blowbyu's Avatar
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    Quote Originally Posted by Joe Stang View Post
    Did a quick check on of compression on my 800 engine, came up with 185 on each cylinder.

    im always running 93 octane in it with some oil, should i put my stock head back on?? I have an r&d rec head on it. Thanks in advance.

    185 compression can be safe on 93, granted your carbs are jetting correctly. I dont have my notes with me at work, but you need to do a squish test. If I remember correctly if you are above .049 you should be ok.

  4. #4
    96XPSS's Avatar
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    Stock pipe? Yes. But make sure squish is .050" or more.

    Just a FYI...I have been running 93 on my 2000 XPL 951 with 185 lbs of compression @ .070" squish for three+ years. Prop bent up 1 degree on the trailing edge too.

  5. #5
    Joe Stang's Avatar
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    ill toss my stock head on for now to be safe, i just rebuilt the engine, i dont wanna having problems Thanks again!

  6. #6
    96XPSS's Avatar
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    Quote Originally Posted by Joe Stang View Post
    ill toss my stock head on for now to be safe, i just rebuilt the engine, i dont wanna having problems Thanks again!
    Chicken...

    Check your squish before swapping so you know what you have.

  7. #7

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    Rq are you runing a level-1 head with a 4 holer?

    TLR

    PS: did your dad survive the storm ok? we had damage at the marina but all is ok for us.

  8. #8
    96XPSS's Avatar
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    Quote Originally Posted by TLR View Post
    Rq are you runing a level-1 head with a 4 holer?

    TLR

    PS: did your dad survive the storm ok? we had damage at the marina but all is ok for us.
    Tim, I don't remember on the gasket...I'll look this afternoon. Whatever GP recommended with his head mill. It GPS'd 64.6 with a 3/4 tank at my uncle's a couple weeks ago. 65.8 with 1/4 tank. And I haven't started tweaking stuff yet.

    My dad didn't mention any damage. He's had wireless issues...been keeping him occupied...lol

  9. #9
    Joe Stang's Avatar
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    Quote Originally Posted by 96XPSS View Post
    Chicken...

    Check your squish before swapping so you know what you have.
    you bet i am

    how do i check squish, this whole 2 stroke jet ski engine stuff is still new to me, but i can build them

  10. #10
    96XPSS's Avatar
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    Hey Joe, get some thick plumbers solder. Cut 4 pieces about 4" long. Bend them in 90 degree "Z". Get the piece going through the spark plug hole to be about 1.5" long, it needs to reach the cylinder wall when in the hole. Lift up and down so that you can feel it sliding up the wall, you want it at the top edge of the cylinder.

    Now...the trick comes in. You need two pieces, placed front and rear (over the piston pins to prevent rocking and an erroneous reading). Place your lanyard on, bump engine over to squash the solder. Remove and check the gap with calipers at the thinnist point...keeping up with which one is in front and rear. If you don't have a thick end you didn't get it to the edge of the cylinder. It's kinda hard to do by yourself, but with a little practice you can get it.

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