compression test

[350xrider911]

i kicked its over 7 times cold came out 160 i have 10.5 compression ppiston in it. i held it open trottle.

[Dirtcrasher]

Pour a tablespoon of engine oil in the plug hole and check it again. If it rises, something is up with the rings. I'm not certain what a 10.5:1 should read but I'll bet it's a bit higher than that.

I'd have that decomp cable off for this test myself.....

[350xrider911]

i can bearly kick it over with out the decompression cable. ok ill try the table spoon. but how would that up the reading if the rings are back wouldnt it seep past the ring if there wronge.

[350xrider911]

ok i tryed it with alittle more effert whit out the decomprsion on and its reading 200 every time i didnt try the tlb spoon. yet

[RedRider_AK]

Well there ya go. Sounds just fine to me.

[350xrider911]

so now i know its the valve guid seals or should i do a leak down test

[Dirtcrasher]

ok i tryed it with alittle more effert whit out the decomprsion on and its reading 200 every time i didnt try the tlb spoon. yet


If you would buy and READ a manual you'd understand.

Air or compression can leak past the rings, but oil will seal it up enough to show the difference.

Look, I have busted your balls ENOUGH........

The majority of machine owners don't have a manual because they rarely have to open the motor or venture into places they don't understand. Thousands of motors are the end of an ATC that works because the owners don't understand the simplest of facts or procedures. I've watched post after post of people asking questions and then they sell the machine over a stupid problem or something they ruined trying to fix it.

Honestly, yes you put in a top end but do you understand all of it? Do you want to? Simple tiny bits of information will make you a better mechanic than your friends.

Do you want to ride? do you want it fixed? Then buy a manual, read it and get the basics. From there, this message board can assist you. But walking you through this crap from A-Z just doesn't work.

There is a guy on EBAY with OEM brand new manuals for 46$ and 8$ to ship. We also have or had a very generous member that had them on CD fo free or a small donation. BUT, the book is awesome and in your hands. I have read countless manuals which allow me to TRY and help you guys but you have to help yourselves also.........

[Rustytinhorn]

First off, you are supposed to do a compression test with the engine hot. That way the piston and rings are expanded and you will get a better seal.
Adding the oil to the cylinder helps to temporarily seal off the rings. This is the method you use in dertimining whether your rings or valves are bad. 160 p.s.i. cold sounds good to me. I saw the numbers that said what p.s.i. you were supposed to be at for certain compression ratios, but I can't remember where off the top of my head.
Once you get it hot I'm guessing it will go up anther 10 psi atleast. Obviously its sealing off correctly, and I really dont see what the problem is. Maybe adjust your decompression cable to have a tiny more slack in it. Other than that it sounds like it is working like its supposed to.

[Rustytinhorn]

so now i know its the valve guid seals or should i do a leak down test

Its not the valve guides and there is no point in doin a leak down test on a 4 stroke. If you could reach 200psi then obviously your bike is operating AT ITS MAXIMUM ALREADY!!!!!

[350xrider911]

Rustytinhorn it smokes on start up. but i put maby a little more then a table spoon the cold setting with the decompresion went up to around 180 but when i didnt do that table spoon it was around 160, so the sounds of this my rings r bad.