Pulled head and found 1 oily combustion chamber

Hello all. I had to pull the head off my bike so that I could helicoil a stripped cam bolt hole. That job is done but I noticed while all the combustion chambers had quite a bit of carbon build up (That I intend to clean off) One of them is oily. What does it mean? is there anything I need to do while I have the head off (valve seals?) I bought a new head gasket and oil seal but do I have to replace the base gasket even though I haven't lifted the jug?

Thank you,
Zac

Valve guide seals yes. What does that bore look like?
Steve

Hears some pictures of the cylinder bore

Need to see the oily one.
Steve

Oops, here it is. Compression before dis-assembly w





as in line with the other cylinders 155

Looks like it had just been honed. Maybe a broken ring. I'd check the guide seals first.
Steve

Compression was 155 in that cylinder before I pulled the head. Right in line with the others. Would it be a lot lower if a ring was busted?

Could be oil ring.
Steve

Dirtyhands wrote: Hello all. I had to pull the head off my bike so that I could helicoil a stripped cam bolt hole. That job is done but I noticed while all the combustion chambers had quite a bit of carbon build up (That I intend to clean off) One of them is oily. What does it mean? is there anything I need to do while I have the head off (valve seals?) I bought a new head gasket and oil seal but do I have to replace the base gasket even though I haven't lifted the jug?

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Hey Zac!
Just curious, could it be possible that "oily-ness" is just penetrating oil that leaked in to that cylinder during the head removal?
The reason I ask is.
1) You mentioned good and equal compression.
2) That spark plug looks pretty much like the other - not all blackened but so-called "coffee and cream" which is good; right?
3) In the photo, there appears to be some shiny hazy glow between the oiling port (where the oblong oil seal goes) that wraps around the cylinder head / bore in question. As though maybe something leaked in and around that head recently.

My vote is to replace the valve stem seals.
Viton valve stem seals are inexpensive and you are there now. I had the machine shop replace them on KZombie's cylinder head a week ago.

Yet to see the oily piston.
Steve

Believe it or not the last set of pictures were of the piston that chamber went with. The Piston is as dry and sooty as the others. only the combustion chamber is oily

Hey wrenchmonkey I think your onto something. Especially since the piston looks normal. I also have a feeling I know when the oil came past the oring. When I was removing the head I tried to follow the manuals advise and pop the head loose by kicking the engine over. I bet the oil squeezed by then. I ordered some viton seals though. I'm honestly considering a new head if I'm pulling valves. There are 3 helicoils in this one and probably more on the way (due to inexperience and overtorquing). A fresh start might be nice.