Topic: oil seepage-leak

[tmart]

Hi guys,I am new to this great forum,it is almost as much fun reading this forum as working on the old bikes,i have a question that may have already been addressed in another post,but here it goes.I have a 73' 350f that runs great,the only problem it has is after about 5 or so miles i am getting a small oil leak on the jug fins that are located at the headgasket.the leaks are only at the left and right side of the engine,not in frt or in back.This bike has only about 45 miles on it since I got it running.The last time it ran was in 1994.The clock has only 15,000 miles on her.Does the bike need a headgasket or do you think after a few hundred miles of running it might seal itself off.It is hard for me to picture a head gasket leaking by looking at the design of the deck,but there maybe something i dont know about this engine that could be causing the problem,should i just ignore it and clean it every few days maybe.Any help would be appreaciated,thanks

[OldSchool_IsCool]

Welcome to the insanity, Tmart!

There is an oil gallery in that area on many of these engines (don't know about your specific motor) that is prone to having it's seals leak.  Unless it is gushing oil, I'd say live with it until you find another reason to tear into an otherwise sound engine.  One coping mechanism I use is to roll up a sheet of paper towel and cram it between the fins at the point of the leak.  Change the paper towel when saturated.  Short lengths of cotton clothes line will do the same if you find you need to change it often.

You can also confirm the location of the leak by cleaning the fins, letting it dry, then spray on some aerosol foot powder.  Run the engine.  The white powder will turn black showing you the exact point of the leak.

[tmart]

Now that sounds like a good idea.We just ride around the local area for fun,its not like we are going cross country or anything.I have another question,that could relate to this problem.The pcv or vent system,how do you check it,I blew into the hose,it is restricted,I apply vaccum and it will hold a vaccum unless i loosen the oil fill cap.Is there a correct way to test this? thanks

[OldSchool_IsCool]

I've never had reason to check mine, but it sounds like it is working properly, especially since it will hold a vacuum until you open the fill cap.  The purpose of the vent is to allow any blow by out of the crank.  Seems to me that confirmation of air flow from oil fill cap thru the vent tube demonstrates that yes, your engine will NOT build pressure due to blow by.

[tmart]

thanks,i will leave it alone then.Appreaciate your help.
Terry

[Bodi]

The 350/400 engine really likes to seep oil at the ends of the head/barrel join. The oil galleries up through the barrel section are very close to the edge, and there's a "oil control orifice valve" - just a plug with a small hole to allow enough oil through to lubricate the valvegear - set in the top of the barrel assembly with a rubber seal. Once the rubber seal loses elasticity from engine heat, full oil pressure gets to the head gasket joint and the seal isn't good enough to stop some from seeping through. The rag/paper towel/cotton cord works fine to sop the oil up before it dirties the engine, I have to change them about every 500 miles on mine.
The latest seal from Honda looks slightly different from original and might work better in the long run and the seal with Athena gasket sets is quite different, but I've changed head gaskets and seals several times on my engine and on other bikes - the leak has always come back after a while. I've tried Hylomar and other sealants applied judiciously around the valve seal without success as well.

[tmart]

Thanks bodi,are you recommending just living with it also,I don't have a real big problem living with it if it is a pain to replace those seals.

[Bodi]

Yeah, live with it unless you're losing a lot of oil. I rarely need to add oil between changes so it is a cosmetic issue rather than something dangerous.

[OldSchool_IsCool]

Loosing a lot of oil or your dry cleaning bill for oily pants becomes a problem.  Maybe consider chaps! 

[tmart]

I like the idea of getting a tampon,painting it silver and cramming it in the fins,super absorbant,ha ha