compression on cylinders

jr_amsoil

jr_amsoil

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Joined
Mar 15, 2006
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364
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Mitchell, SD
took my sled into the dealer today to have variflow put on and powervalves cleaned. they call me later in the day and tell me i only have 100 lb on each cylinder. but if they are equal i think they should be fine it was very cold today and hasn't been ran all summer a mechanic i know told me not to worry about it. he said being cold today and from sittin all summer would maybe make it that way. he also said testers can vary alot so i would like apinions from other people.
 
mmmmmm make a run with your sled and check it back but its very low ...but sometime after the summer the cylinder are very dry and it lower the compression
 
i was told to lube the pistons also and he said that would help. it seems like it still has really good power though.
 
yes if cylinder are dry it lower the compression but make sure to have a look again after a ride
 
somewhere around there. but take it for a ride and test it again and if it is the same just change the rings. They are really cheap and it will get your numbers back to what they are supposed to be.
 
The "Dealer" just wants to sell U some parts, if its the same dealer I'm thinking of. Why didnt U install the variflow and clean the powervalves yourself???????Must have money falling off the money tree again. :homework: :D:DP
 
usually if all three are within 15% u should be fine...but 100 does sound pretty low. according to my research it should be between 125-135
 
cacsrx1 said:
The "Dealer" just wants to sell U some parts, if its the same dealer I'm thinking of. Why didnt U install the variflow and clean the powervalves yourself???????Must have money falling off the money tree again. :homework: :D:DP
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yea it is studdering studer who i brought it to i think if anything i will just put rings in today they told me the compression was 100 110 and 115 so who knows with dealer i need to see the tester with my own eyes before anything gets done.you must of had a bad encounter with palace also.
 
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dont trust the dealer check the comp yourself or watch it get done, if the numbers are still low then ask for it to be done with a different tester.

make sure to remove all plugs, and when pulling over hold the throttle wide open.
 
what ever happendd to the wet test? i thought if you put a tea spoon of oil in each cylinder and the compression jumps up alot that it is time for new rings. I never hear anybody talking about this test.
 
First time I ever heard that. I would think that adding oil to the cylinders would increse compression if the rings are good, and not change mutch if they are bad.
 
I would just buy a compression tester and do it myself. I did. I don't trust the dealers anyhow. By the way....why does the throttle have to be wide open when pulling it over?
 
If someone has low comp on a fourstroke, they pour a little oil in the cylinders and test again, if the comp get`s much higher then they say it`s the rings, if it doesnt then it`s a busted valve.
However, all engines will make higher comp numbers if you pour some oil in them, so even if the number increases after trying with oil, it doesn`t mean that your rings are worn out.
On my SRX 700 I had 125 on all three.
Get your own tester, like someone mentioned above, dealer might like to sell you some parts.
 
oil can also make a valve that doesn't seal behave better.

make sure that it's up to temperature and with the throttle wide open when you test. Thing is that every gauge reads abit different, so you never really know. All you can do is compare hot to cold, and wet to dry to get an idea of the health of the motor, even that is really firing in the dark tho, a proper leakdown test is the only REAL way.
 
Junior said:
oil can also make a valve that doesn't seal behave better.

make sure that it's up to temperature and with the throttle wide open when you test. Thing is that every gauge reads abit different, so you never really know. All you can do is compare hot to cold, and wet to dry to get an idea of the health of the motor, even that is really firing in the dark tho, a proper leakdown test is the only REAL way.
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yep, well said. Make sure the engine is warm not hot, you want to still be able to keep your hand on it.
 
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