HELP Valve Cover Gasket Seating

[Guest]

I've got a Real Gasket, silicone gasket, and it doesn't like to seal above the moons. Everytime I torque (15-in/lbs) the gasket down, it either pukes out above the moons, or waits until I've travelled 20 minutes at 5500 rpm (70 mph) before sliping out and dumping oil on my leg.

Anyone else have this problem? It's on an '80 GS850GL. I think it'll be worthwhile to go back to paper.

[Riding Again]

Forgot to add that this has happened twice, above different moons. Left front and right rear. The gasket is a week old. The first time I got to a buddy's house who's a machinist (100 miles away) and made a part to fit between the moon cap and the cover to prevent it from slipping out again.

Should have made four of them.

[chef1366]

Try a little RTV on the half moons. A little!
Is the gasket getting pinched out with too much tourque?

[Riding Again]

I hope not. I've applied what was asked for, 15 inch/pounds

[Skyboy8950]

Crap, I just ordered one of those...

[bwringer]

Two hints for these:

Use old half-moon seals if possible. New ones are designed to compress a certain amount under a paper gasket with about five times more torque on the bolts. Old ones are "pre-compressed" and will fit better.

Also, clean the half moons and the place where they slot into the head, then install them with a wee bit of non-hardening case sealer on the rounded part (not on the straight part where the gasket goes across). This will help glue them in place and seal them.

I'd try to avoid using RTV unless you're trapped in lower BFE and it's the only sticky substance around besides horse dung and spit. If you do need to use this evil stuff, use VERY VERY little.

Some also advocate turning the half moon seals around so the lip is on the inside, but I haven't done this since on the bikes I've worked on, it didn't look like there's enough room between the end of the camshaft and the cylinder head. YMMV.

[Riding Again]

I rode it to work today (darn, accidently let the 4-wheel registration expire) kept it below 5000 rpm and monitored it. So far no problems.

Found a reference for those without torque wrenches to tighten finger tight and then 3/4 turn in the posts (searched using valve cover gasket or real gasket, it was late, and found it on the 7th or 8th page in).

Packed a couple of rachets, etc in my camelback just in case. Rechecked the tightness after 20 minutes on the back roads and found a couple loose and retightened. No leaks yet I believe, but a bunch of oil coming out of hiding from the last one.

Leaks are all above the moons, not from the moons.

[ryonker]

After my valve check I had leaking half moons. I applied that RTV stuff and haven't had a leak since.

Rick