Author Topic: Oily plug? (Leaky Cylinder Head Cover)  (Read 1265 times)

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Offline LastChancer88

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Oily plug? (Leaky Cylinder Head Cover)
« on: May 30, 2019, 10:48:21 AM »
Just looking for insight into this.  plug #4.  I just replaced the cylinder cover gasket.  Used the rubber band trick to put the cover back on.  I dont think the oil is from there.  I put a screwdriver into the cylinder and I would assume this is too much oil to come out?  Maybe coming up from around this bolt next to it?  The first photo looks less oily than the plug really was.
« Last Edit: June 09, 2019, 01:46:42 PM by LastChancer88 »
1973 Honda CB500 Four
1973 Suzuki TC125

Offline dave500

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Re: Oily plug?
« Reply #1 on: May 31, 2019, 02:31:58 AM »
is the motor smoking?have you ridden it pretty hard and long?or just idled it and revved it in the driveway?

Offline LastChancer88

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Re: Oily plug?
« Reply #2 on: May 31, 2019, 09:03:06 AM »
is the motor smoking?have you ridden it pretty hard and long?or just idled it and revved it in the driveway?

Not ridden hard just around a few blocks or so.  I'm not really a full throttle kinda guy.  I've just been test riding and tuning after a few short rides.   My current idea is to clean the engine and then try to pinpoint it but I was curious if anyone had an experienced take on this symptom.
1973 Honda CB500 Four
1973 Suzuki TC125

Offline pjlogue

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Re: Oily plug?
« Reply #3 on: May 31, 2019, 10:10:55 AM »
I would clean up the area with carb cleaner, let it dry and then run it for a short bit and see if you can find where it's coming from.  Blowing talc powder on it after you clean it well helps seeing where its coming from.

-P.

Offline disco

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Re: Oily plug?
« Reply #4 on: June 04, 2019, 12:51:21 AM »
Check that the needle & set for that carb is working properly. I just went thru the same thing with a constantly “oily plug” which eventually would be overcome and then wouldn’t fire. Turns out the needle & seat was allowing more & more fuel in, which I mistook for an “oily plug”. Changed needle & seat, and now all good.
1976 CB750 K6 Sapphire Blue
1972 CB750 K2 836 Orange Sunrise
1972 CB750 K2 Candy Red
1972 CB750 K2 Candy Gold'

Offline LastChancer88

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Re: Oily plug?
« Reply #5 on: June 09, 2019, 01:46:13 PM »
Well unfortunately I was able to determine that the leak is coming out of the cylinder head cover inside the side cover above the 4th cylinder spark plug.  I was really hoping it was just the side cover's o-rings but it's definitely not.  Would there be a reason other than the cylinder head cover's gasket being bad/misplaces that would cause this?  My plan is to spend a day opening it up again to inspect but I won't have time for a little bit.  We're talking a pretty significant amount of oil that came out while it was running not just drip drip.  I did one quick test ride after I thought I had fixed the issue with new o-rings on the side cover and the whole right side of the engine was shiny with oil.  She's parked now till I can figure this out. 

The only thought I have is the cylinder head gasket popped partially out when I installed it.
1973 Honda CB500 Four
1973 Suzuki TC125