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Discussion Starter #1
I have a 1994 Polaris XLT. Just rebuilt the top end and crank. stock bore but new pistons and rings. Warmed the sled up held the throttle wide open and pulled till the PSI stopped going up. I had 160 accrossed all.

Is this high for just new pistons and rings?
 

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seems pretty high
the best way to check is turn your key on and take your plugs out and flip the kill switch up and pull it over a bunch of times .160 seems really high
 

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You should be in the 125 psi range for that sled. Were the pistons OEM?
 

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Discussion Starter #6
well im not sure about the cylinders i dont think anything were done to them. i bought it on ebay after my old cylinders had to be bored more than .020 over..

and yes they are oem pistons and rings.

i dont think it is the compression tester because my friends sled has about 130 accrossed. ill have to pull out the other tester and test again.

any other ideas?
 

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Discussion Starter #8
Im bought the top end gasket set from cometic said xlt 580 right on the wrapping so im pretty sure it was right. if it was the wrong gasket wouldnt it be a loss of compression?
 

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A thicker or thinner gasket will definately effect your compression. If it said XLT 580 on it then it's probably right.

Is your oil pump stuck wide open. Lot's of Xtra oil in the cylinder will make the rings seal really well and bump your compression numbers up really high. You see this sometimes if you compression test a motot on the bench right after reassembly...from the assembly lube.

It's definately a long shot.
 

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Discussion Starter #10
well i added some oil to the gas for breakin.. wonder if that made that much of a difference. ill check the oil pump
 
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