small oil leak at cyl head

I have a small amount of oil seepage on the left side of the engine at the gasket for the cylinder head. Is it OK to leave as is, or should I try to torque the bolts (as one post suggested).

Is the leak at the valve cover or is it at the cylinder head Base gasket?




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It certainly would do no harm to insure that the head nuts are torqued to spec. Do not over-tighten them.

the leak is not at the valve cover. It is on the left side between the cooling fins where the base gasket is. It is doesn't appear to be much oil at all, just visibly moist. There is not a leak in the same position on the other side.

what would be the correct procedure for torquing the head nuts to spec? Do you have the torque spec for those?

thanks

What bike?

gpz550.

I checked the torque on the cyl head nuts, and they all seemed tight enough (according to spec in the manual i found online: 16.5 ft-lbs for the 12 cyl head bolts).

Here is a PDF copy of the factory manual you can download for free. It covers 1979-1983.

www.kzrider.com/service-manuals

It is on the left side between the cooling fins where the base gasket is.

I have a "visibly moist" area at the base gasket behind cylinders 3 and 4.
The base gasket is at the base of the cylinders between the cylinders and the engine cases or gearbox.

Is this where your leak is?


I can poke a bit of kleenex or paper towel in ther once a week and see it come out oil stained. Never enough oil to drip. It has been like that since i bought the bike 15 years ago. Bike runs fine, compression is good - not that I would expect a small base gasket leak to effect compression. For me its not worth the trouble of tearing it down to fix. And will wait until or if i need to do a major overhaul

JR, I'm sorry for not explaining clearly. Another person had written "valve cover or cylinder head base gasket," and I think that my use of "base" confused matters. the leak is not at the base of the engine block, it is on the side of the engine between the engine block and the cylinder head. If you were to remove the cylinder head, there would be a gasket there, and this is where the small amount of oil moisture is appearing--viewed from the left side of the bike.

I have had the bike about a year and have noticed it and never thought much of it, but now I'm just wondering if it is something to address. I have never checked compression, but the bike pulls strong. Is a leak at the gasket between block and cyl head more concerning than base gasket? Removing the cyl head appears to be more of a job than I'm up for, based on what I've read in the manual.

Is it on the left side? There is always an oil buildup on the left side of the engine when the engine is left on the side stand. Try leaving the bike on the center stand and watch for the oil leak. If it disappears then it's just due to the oil buildup on the left side when the bike is leaning that way. If it still weeps even when the bike is left on the center stand then you can either live with it or pull the head and change the gaskets.

Yes, it is on the left side. However, the bike didn't come with a center stand--the PO removed that. I didn't realize that there could be a noticeable leak from parking on the side stand, but that's good to know. I think I'll to not worry about it for the time being.

Had a similar issue on my KZ1100 after I first brought it home. Turned out the problem was the o-rings between the top of the cylinder and bottom of the head. On the 1100 they seal around the outside studs for oil return.

Looks like the 550 has a different arrangement but still uses some type of o-ring, part number 92055-1147. Might be worth investigating.