GY6 150cc where is the oil coming from?

Posts: 21

I am at either the point of shooting myself or selling this Kart.

I have just successfully replaced the piston rings since it was suspected as the number one culprit for oil on the spark plug and massive amounts of carbon in the combustion chamber. This went well and I was very careful. Changed oil, put it all back together, and she fired right up. Ran it up and down the road a few times at full speed getting it up to temperaure and all seemed well. Exhaust was not smoky, and breather wasn't smoking. Decided to make a slight valve adjustment, and ran some more and then it began. the smell of oil coming out and on to the exhaust pipe. Very slow. shut down, checked plug and found oil again all over the plug. Cleaned it up, let it idle for 15 minutes and no oil. Took it for another hot run up the road, and oil started showing itself again. Hard to tell, but it appears it is coming out around the flange on the exhaust. Plus I'm smoky out my exhaust pipe again. Gaskets look good. Evil or Very Mad

What else can it be? I can only come up with one more idea which most people I spoke with said it was highly unlikely, and that is the Valve guide seals. Thinking that on the intake stroke I am pulling oil in. Another unknown for me; the breather on the tappet or valve cover (first cover to remove to adjust valves) is puffing air out all the time. Is this normal. I was told if that was blowing smoke, I definately had piston rings that were shot. plus I had a history inititially when I first ran this kart of a significant amount of dirt getting into the carberuator, so it all made sense. When I first fired this engine up after the Piston ring job, no smoke. now it is slightly puffing smoke. what is normal?

I don't want to give up, but nor I or my kids are having any fun with this kart at this time. Any Ideas on what to do next? Or suspicions? ask away if it helps. Can't hurt my feelings.

Posts: 4216

a little oil on the plug and smoke from the exhaust is normal when a new set of rings are installed. does it smoke really bad and is the plug fouled to the point the engine quits due to lack of spark?

check the o-ring on the cam chain tensioner. oil will come from there. the breather hose is supposed to blow out air or built up crank case gas, a little oil there is normal.

the head has valve guides no seals. so if the guide is warn on the exhaust valve then oil will get into the cylinder and out the exhaust

Posts: 21

no, the plug is not fouled, nor have I ran it long enought for that propably to occur. I am confident it will eventually, as everything is acting as it was before the piston ring change. No oil coming from the chain tensioner.
The breather is blowing out pretty strong, and has a strong pulse about it, like it is matching the stroke of the piston. where does this pressure and pulsation coming from?

What I don't understand is; If the Valve guides are good, how could any pressure or pulse accumulate in that outer teppet chamber where the cam, chain, rocker arms, breather, etc. are ?

I am assuming since I have oil on my plug it is coming from the exhaust port and leaking around the exhaust pipe flange. It is so dificult to determine it's origin. It is only significant , when i crank into it, and drive up the road. Idling, isn't a problem.

Posts: 4216

ok, pull the fan plastic off and look at where the cylinder meets the case. and also look at the bottom of the valve cover

Posts: 21

No, Nothing at the valve cover and nothing at the case.
I only see oil around the exhaust port.

Regardless, I still don't know the answers I posed on the previous posting. I'm hoping someone can answer. I want to be sure everything else is good and what I described is acceptable.

Thanks BIGE, I need all the help I can get!

Posts: 648

I'm betting you have a warped head. sucking oil through the head gasket.

Posts: 4216

that was going to be my next thought, go going charlie makes sense to me

Posts: 21

well, I guess we all don't want to hear there is the chance of a warped head.
But does anyone know about this:The breather is blowing out pretty strong, and has a strong pulse about it, like it is matching the stroke of the piston. where does this pressure and pulsation coming from? is this normal?

If the Valve guides are good, how could any pressure or pulse accumulate in that outer teppet chamber where the cam, chain, rocker arms, breather, etc. are ?

I'll live with the fact I have a warped head, but I should point out that I used head gasket sealant along with the gasket. This was done in hopes of any descrepencies on the face. I had a straight edge pulled across it and it only appeared that at one corner it possibly was out a thousand or two, but so slight it was so difficult to see. wouldn't it have to be out quite a bit? Thoughts?

Posts: 648

Posts: 21

Thanks Ckau, Thanks to all you guys. I'll tear it apart one more time. Maybe I'll just order new parts and then deal with the old ones later, as you suggested.

Now, I am confused how this could have occurred. I would imagine that only by the engine overheating. I never had any indication of the engine overheating or reason for it to overheat. I know that I had oil on my plug from the beginning, so I am curious if this head could have come to me this way? Possible? maybe worsened over time. and should I totally just forget the idea of valve guides leaking bye?
Now on top of those questions, how dang important is that plastic guard that wraps around the engine assembly. I was thinking it served a purpose in cooling the engine. In doing all this repair work recently, a screw came out on the exhaust side of this shroud and it fell down and burned off a section on the exhaust pipe. Now the bottom right corner of this shroud is not present because it was originally one whole piece and there is nothing to support it near the bottom to keep it in place . basically the whole bottom shroud assembly is now in two pieces. So, Is it imperitive to order a whole new shroud assembly? thoughts? Confused