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Valve cover leak

D

dion1951

Member
Just adjusted the valves on my 80 R100s. Gasket on one side had a slight tear on it so I bought a new one and installed. Surfaces are clean. Put new gasket on and now I have a pretty good leak after start up. I don't remember ever using any type do sealant before. Should I? Or ride it around the block and see if it goes away?
 
Sounds kinda messy. That, and your H-D riding friends will invite you to park with them.... :bolt

I'd go back through the whole drill; remove the valve cover, re-clean all the surfaces (and inspect carefully) and re-install. Pay particular attention to snugging down the center bolt in steps and in conjunction with tightening to two 6mm nuts...

Tighten the center nut a bit,

then tighten the two 6mm nuts...

then tighten the center nut a bit more...

then tighten the two 6mm nuts a bit...

Just don't over do it. No sealant required.
 
Any of the 3 bolts in question stripped?

All 3 have wave washers underneath them? Watch when you tighten them (most over tighten). The wave washers need to compress ever so slightly (and it does not take 6 ft lbs of torque, either).
 
I'd double check things by removing the cover looking for some missed old gasket etc. Perhaps "witness marks" on the new gasket will lead you to the proper diagnosis. Watch out not to over tighten.
 
I'm the 3rd owner of 76 R90/6 now with 120K miles. I switched to silicone valve cover gaskets 4 yrs ago due to leaks. That solved the problem. Now have been using silicone gaskets on both bikes and no leaks. Must go on dry and DO NO OVER-TIGHTEN ANY NUTS!:thumb

Mike Horne
76 R90/6
93 R100R Legend
 
Just pulled the cover off and inspected head and valve cover surfaces. Looked good to me. Put it back together and went around the block and parked. Still about a tablespoon of oil that drips out. None of the bolts are stripped. Owned the bike for 13years and always done my own valves and this is the first time I've ever had this problem. I probably have the nuts tighter than I normally do just because of the leak. Maybe I should loosen it up one more time and retighten but not quite as tight?
 
Are you sure the valve cover is not on upside down from its typical position? I recently fixed a (long time) leaking valve cover by cleaning the head and cover then using marking compound (in this case cheap women's lipstick) to locate the high spots on the valve cover and sand them down. Since yours has not leaked until now, I expect the valve cover is upside down. I found one quick way to tell the orientation is by looking inside the cover where the most grime from the normally up portion collects near the center stud hole. Good luck!


Edit: Well, it turned out my long term oil leak was *not* from the valve cover gasket after all. After thoroughly cleaning the cylinder and inspecting for leaks, oil drops still fell on my boot when riding! It turns out the pressed oil return tubes in the head were the source. Following a Harley bike thread, took some brake cleaner (the CFC type), sprayed the lower head area around the tubes to degrease and clean, took some loctite 290 on a saturated q-tip and swabbed the tube/head joint. I think the leak is fixed. Feel like a Harley owner now.
 
Last edited:
I've used silicone gaskets for years on both the valve covers and oil pan. They do not need much tightening, which also lessens the tendency to strip the bolts.
 
Get everything solvent clean and take the bike out and get it hot..up to operating temp and see if that helps. I found that new gaskets need to get hot to seal.
 
Rode it to work (6 miles). Still dripping. Ordered set of silicone gaskets. Will see if that does the job. Thanks for everyones help.
 
You shouldn't have been able to "inspect all surfaces" as the OE gaskets have heat-activated adhesive on one side (the side with printing) and if it had activated an "inspection" would ruin them. The side with adhesive goes toward the head. I've had these gaskets work fine for over 10 years at a time.

IMHO the only useful application of silicone gaskets is for the oil pan. They're a PITA to work with on the heads and gasoline immediately destroys those used on float bowls.
 
Hmmm. Didn't know there was an adhesive side. When I put it on first time only started the bike and then shut it down. Just wanted to pump some oil into the valve cover so it didn't get warm at all. I did ride it to work and back tonight though. Maybe I'll pull the cover one more time tomorrow just for the heck of it and see which way I put it on. Can't hurt anything I suppose.
 
IIRC, the writing side on the gasket has the heat-activated sealant, so the lettering should face the heat source (ie, the head). This lets the gasket remain in place whenever the cover is removed. The side opposite the lettering should have a graphite layer which minimizes sticking so the cover can be removed without pulling the gasket off. That should be the case with OEM gaskets.

The gaskets on my /7 are original and one or both sides don't remain stuck anymore. No matter...I don't have any leaks in this area.
 
Different experience with silicone gaskets.

Some years ago I decided to use silicon gaskets for no apparent reason except they had a cool reddish color.

AND THEY LEAKED!

I used different torque settings for the center nut and the side nuts but no change. Put OEM gaskets on and no problem. YMMV!

Q: Where exactly is the oil leaking? Through the gasket?

/Guenther
 
Got home from work today and the silicone gaskets were in the mailbox. Put one on the leaking side and took a short ride. No leaks. Then I celebrated by going to see ZZ Top at the Majestic in San Antonio. They can still crank it out!!
 
Put one on the leaking side and took a short ride. No leaks.
Click to expand...

With the opposite side in mind, remember old saw, "If it ain't broke, don't fix it."

Just sayin'
icon_wink.gif
 
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