I figured it should have been much higher. Im wondering if it's my head gasket or if it actually is blowing by the rings. There is no sign of blow by though. We have another four wheeler that has blow by and it spuders at high rpm. So I'm really not sure at this point.

Thanks for all the help so far.

 

squirt a little oil in the cylinder and retest the compression,if it goes up, you have bad rings, the oil will help the rings seal for the test. If the compression does not go up, you either have a bad head gasket, as stated before, or your valves are so tight, they are slightly open, and leaking compression.

 

Okay, I will try that tomorrow. What type of oil do you suggest?

 

regular motor oil works fine, put about a teaspoon in, or if you have a oil gun, give it 2 or 3 good squirts, you want a good coat of oil to get down to the rings.keep us updated on what you find.

 

Update- I put oil in the cylinder and no change in compression. But all the sudden it starts up on the electric start. So i'm not sure if it's a fluke or something that is just occurring today? But I will have to try it again tomorrow. But we'll see.

 

So i have just got my shop Manuel in and it say that compression should be in the range of 169-199. I'm like 100 psi too oh well. guess i will be doing a top end overhaul.

 

Are you sure that is in PSI, and not some metric measurement? 160-199 is in the realm of a very hi comp race piston, stock should not go over 120-135 max PSI, Hondas usually run a 8.2:1 or 9:1 piston,no way that would go over 140 brand new.

 

the Haynes book say's
11.9 kg/cm2 to 14.0 kg.cm2 (171 to 199 psi)

So i don't know

 

Yeah, Mine says the same. Maybe you don't need a top end overhaul. Maybe just a valve adjust?

Here's a cool link.

http://www.dansmc.com/MC_repaircourse.htm

 

Hello hot rod...I am new to the atv world...never worked on them much, but I have overhauled and worked on many other mechanical modes of transportaions....like snowsleds...anyways....before I even read down to the other responses my first reaction was rings....low compression....if it starts hard cold that is a sign but also the valves like others suggested....but I would lean towards the compression or lack of because you said when it warms it will start better....that is the metal expanding and making it slightly tighter tolerances....it probally wouldnt hurt to do a ring job anyways of it has miles on it.....well just a thought....keep us posted.....Maine