Slight oil leak from alternator cover....not the gasket

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Slight oil leak from alternator cover....not the gasket

maybe73
1975 cb 750. Not a bad leak but annoying. Thought I just needed a new gasket, simple enough... Nope... There are two " D " shaped grommets on the stator/alternator wires where they enter the engine case. They fit flat sides back to back. Mine are split and small pieces of these grommets are gone. I can not find replacements. These are special shaped for this fit. Even called Ricksmotorsportelectrics.com and they don't have them either, they reuse old ones. Except for salvage yards, any one have any suggestions? I thought about try to fill the old grommet with gasket sealer but don't think it would hold on all ready very oily surfaces.        Any one else ever have this problem? Man my posts get long. Thanks
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Re: Slight oil leak from alternator cover....not the gasket

TOOLS1
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This is one of the very few times I will ever say "use RTV silicone".
TOOLS
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1976 CB 750-A X 2
1977 CB 750-A X 4
1977 CB 750-K
1976 CB 750 F
1981 CB 750
1966 Kawasaki SG 250
1981 KZ 750 LTD
1973 CB 350
1979 CM 185 Twinstar
1982 Honda XL 80
South of Eden (Kansas City MO)
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Re: Slight oil leak from alternator cover....not the gasket

maybe73
I have heard from others on here that RTV silicone will break down into tiny pieces and end up where we don't want it. I understand your reply and this might be my only option. I will use it sparingly and give it a try. Or... just except the fact that this Honda has a little Harley Davidson in it's soul and is going to mark it's spot where ever I go. Thanks again.
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Re: Slight oil leak from alternator cover....not the gasket

LukeM
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I'm wondering if you can use some other type of neoprene or equivalent grommet to fit in that space. Since there is oil and gas around this part, regular rubber grommets may not work well. I agree that RTV does tend to creep and run a bit, but should be OK after adequate cure time (24-48 hours, if memory serves).

I'm also guessing that the factory part for that grommet is no longer available (since we're talking about 30+ year old machines)?

Luke M
Used to have a 1979 CB750L, sold it as a parts bike, now riding a slightly modified 1984 VT700C. Network/Field Engineer. Central OH, USA, Earth, Sol System, Milky Way Galaxy, Universe.
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Re: Slight oil leak from alternator cover....not the gasket

maybe73
I contacted Permatex, the makers of all things to seal your life. Explained my predicament and was told to use good old black silicone sealant. Good to above 400 degrees and able to withstand the oil and environment that  I'm subjecting it to. Must clean all surfaces of oil, grease, grime. Not an easy task because of the wiring, but I can use some denatured alcohol that is a great oil cleaner and is not to harsh on these old wires. Also as LukeM suggested-complete curing time. Thanks again.
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Re: Slight oil leak from alternator cover....not the gasket

LukeM
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Depending on how neat you want it to look, it may be helpful to build a little mold or dam out of fish paper or stiff cardboard or poster board inside the alternator area.  Line it with wax paper, and position it so you have enough to fill in the hole, and a little more.  Put the alternator cover back on, route the wires, and pour in black silicone.  Wait 24 hours or more.  Remove cover, and peel back the mold and paper.

Denatured alcohol is probably your best bet for cleaning the wires.  Simple Green may work as well, but I don't recall if it leaves any residue behind.

Thanks for calling the Permatex people.  Good customer service on their part.
Luke M
Used to have a 1979 CB750L, sold it as a parts bike, now riding a slightly modified 1984 VT700C. Network/Field Engineer. Central OH, USA, Earth, Sol System, Milky Way Galaxy, Universe.
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Re: Slight oil leak from alternator cover....not the gasket

maybe73
This repair is not visible but I still like to do things the right way. I have to make sure the it doesn't leak oil and since I'm replacing the alternator gasket I don't want to do this repair ever again even though it isn't difficult. And yes on Permatex customer service, live person answered the phone, put me through to technical support and they were knowledgeable and willing to help.
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Re: Slight oil leak from alternator cover....not the gasket

vingtsous
In reply to this post by maybe73
Had the same issue on my 76k....

Used old black silicone sealant has my mechanic (old honda service guy) said...

seems to be ok but motor has'nt work for many hours yet....

I allowed it 2-3 days to cure..

Good luck!
1976 cb750 k6  (rebuilding)
1972 cb750 k2 (project)
1986 kawa ex500
1987 shadow 1100
2005 suzuki katana750
2008 klr650
2009 pair of adidas

Québec
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Re: Slight oil leak from alternator cover....not the gasket

shinyribs
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Any time you need to seal something and it get to the point where you think you NEED to use silicone...don't. Use Indian Head gasket shellac. It will seal ANYTHING that needs sealing and it is unaffected/won't break down in oil. It will even hold up against diesel.

http://www.permatex.com/products-2/product-categories/gasketing/gasket-sealants/permatex--indian-head--gasket-shellac-compound-detail