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Discussion Starter · #1 ·
Hi,

I have a 125cc and I’ve recently noticed a small amount of oil on the top of engine.

I keep clean the oil off but when I start the engine again,the small amount of oil reappeares!

I’ve attached an image to show where the oil is.

I just need to know what the cause of oil leak is?

Thanks

68195
 

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Valve cover gasket is leaking, which is far better then having it leak about 2 inches lower, because then it would be a cylinder head gasket leak. Take that top part off, clean it all up and torque it back on with a tiny bit of gasket sealant.
... there is no pressure there unless your crankcase ventilation is plugged.
 

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Discussion Starter · #3 ·
Valve cover gasket is leaking, which is far better then having it leak about 2 inches lower, because then it would be a cylinder head gasket leak. Take that top part off, clean it all up and torque it back on with a tiny bit of gasket sealant.
... there is no pressure there unless your crankcase ventilation is plugged.
thanks. That’s what I thought as well. I bought a valve cover gasket lastnight from eBay.

so will be replacing that when it arrives.

Just out of interest, why head gasket leak is not good? does that mean I’m gonna have to replace the whole engine?
 

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thanks. That’s what I thought as well. I bought a valve cover gasket lastnight from eBay.

so will be replacing that when it arrives.

Just out of interest, why head gasket leak is not good? does that mean I’m gonna have to replace the whole engine?
There could be any number of reasons, Wasn't installed properly last time, just doesn't work that good, maybe overfilled with oil at one point and that was the weak spot. No reason to think you would have to replace the engine. I bought a brand new $8000.00 engine from a major U.S. manufacturer years ago that leaked from the front valve cover. They recommended another brand gasket which worked perfect. Sometimes it just is what it is.
 

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Just out of interest, why head gasket leak is not good? does that mean I’m gonna have to replace the whole engine?
Head gasket has to keep engine combustion pressure inside the cylinder and engine oil under pressure that it going to the valve train to lubricate that. Pressures are very high and temperatures are extremely high. Loss of pressure at the head gasket is going to stop you riding.
Valve cover gasket is what you have leaking and there is no pressurized anything in there for it to seal in, just hot oil splashing around trying to return to the crankcase by gravity. A fault in the valve cover gasket will leak oil but it won't stop you from riding.

... was this engine made in China or Taiwan?
 

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Discussion Starter · #6 ·
Head gasket has to keep engine combustion pressure inside the cylinder and engine oil under pressure that it going to the valve train to lubricate that. Pressures are very high and temperatures are extremely high. Loss of pressure at the head gasket is going to stop you riding.
Valve cover gasket is what you have leaking and there is no pressurized anything in there for it to seal in, just hot oil splashing around trying to return to the crankcase by gravity. A fault in the valve cover gasket will leak oil but it won't stop you from riding.

... was this engine made in China or Taiwan?
I believe it’s Chinese.

it’s a pioneer nevada which is a Chinese bike.

I bought it as a project and have been working on it for a while now. I basically turned it into a custom bobber.

The engine on these is cheap enough to replace.
 
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