Engine head oil leak around gasket??

[Benjamin Cox]

Hello, I have an 80cc engine bicycle kit and I have an oil leak around the head of the engine located at the head gasket, why is this happening? Is it normal? Should I get it replaced? Can I run it like that for extended periods of time?
Those are my questions....

 

[DAMIEN1307]

I have an oil leak around the head of the engine located at the head gasket

How old is it?...Is it broken in yet?.

why is this happening?

Have you retorqued the head bolts to 144 inch pounds during break-in period and periodically threafter so that the head gasket itself doesn't leak???...Regular motor vibration causes the fasteners on the studs holding the head on the jug to loosen and leak This will also cause the motor to run improperly as well...This is probably why it is happening.

 

[Benjamin Cox]

How old is it?...Is it broken in yet?.


Have you retorqued the head bolts to 144 inch pounds during break-in period and periodically threafter so that the head gasket itself doesn't leak???...Regular motor vibration causes the fasteners on the studs holding the head on the jug to loosen and leak This will also cause the motor to run improperly as well...This is probably why it is happening.

Still in the breaking in period, and yes, i have torqued the head safely

 

[Greg58]

A lot of times the head surface is not flat, I sand every head on sandpaper taped to a thick piece of glass, sand in a circular motion till any high spots are gone. I've found some out of the box that were warped bad, it looks as though someone tightened the head nuts with an impact at the factory.

 

[Benjamin Cox]

A lot of times the head surface is not flat, I sand every head on sandpaper taped to a thick piece of glass, sand in a circular motion till any high spots are gone. I've found some out of the box that were warped bad, it looks as though someone tightened the head nuts with an impact at the factory.

Ok, I'll give it a try tomorrow morning and let you know an update

 

[Chainlube]

A lot of times the head surface is not flat, I sand every head on sandpaper taped to a thick piece of glass, sand in a circular motion till any high spots are gone. I've found some out of the box that were warped bad, it looks as though someone tightened the head nuts with an impact at the factory.

Examine the head gasket too, if it's badly deformed you'll have to replace it. You might be able to bang it and file it and get it to seal for a few days until a new one gets to you.

 

[weefek]

Follow what everyone else here has said. I used 600 grit wet sand on my last head and now it seals well.

Also, check to see the alignment of the head gasket vs sealing surfaces. They dont overlap much (depending on the head). See the picture notice how the ring of oily is offset from the sealing surface. I had to rotate the gasket 90 degrees to get it to seal.

 

[Greg58]

One of the problems I've found can be seen in the picture above, the gasket does not fit the cylinder properly, notice the spot where only half of the sealing surface was making contact. A gasket that is 47mm at the bore would seal better.

 

[Cisco]

Also, make sure that you stack the head washers correctly (usually two flat washer and a lock washer per stud). The stock M8 cap nuts have only 8 threads and a 10mm depth. Check to be sure there is less than 10mm of stud above the washers or else you will just be tightening the cap nuts onto the ends of the studs, and not actually torquing down the head. I use tall acorn nuts with 10 threads and a 12.5mm depth. I use just one flat washer and one lock washer per stud. Use blue thread locker (smurf blood) to keep fasteners from vibrating loose.

 

[noah9988]

It's been my experience that even with flat surfaces and proper torque they can still leak. You might want to just get some gasket maker/dressing.