valve cover half moon end caps

[loudest143]

Bike: 82 gs850g, 4 into 1, emgo pods.

I've been spending some time getting my carbs balanced, and finally got close to where they need to be, when out pops one of my half moon end caps!

Seriously, popped right out. I've got a Real Gasket silicone gasket, and the moons were new when I put that gasket in when I replaced the valve head back in September, so they're not old. (oem part, too)

I've read all about adding some silicone to the half moon to help them stay in place. I've applied the high temp black silicone, and will let them 'cure' while I wait for an oem replacement valve cover gasket, as the Real Gasket has a couple of small tears, and I'm not gonna re-use it.

I thought I read somewhere on this forum about someone putting in the half moons backwards, with the flange on the INSIDE of the head. Seemed kinda risky to me, as it might become a friction point, and fail.

I'm hoping maybe someone can offer up some tricks that they've used to keep these buggers in place. I'll be waiting for the gasket for a few days, so I've got time to try different ideas.

Thanks in advance.

loudest143
yes I used the search engine.

[Nessism]

As long as you cleaned the half moon and cylinder head to remove the oil before applying the sealant you should be good to go.

[BassCliff]

Hi,

And put your sealant only on the curved part of the half moons. That way it doesn't stick to the valve cover gasket. (I love my Real Gasket.) It won't hurt anything to turn your half moons "inside out". But if it popped out on its own, you might want to check the breather tube and make sure it's not plugged. Sometimes the tube on the airbox can get rusted or grungy on the inside and clog. This could raise the pressure in the crankcase and oil will want to start squeezing out wherever it can.


Thank you for your indulgence,

BassCliff

[posplayr]

is your valve cover breather plugged maybe?

[Tom MLC]

Yes, install them backwards. They will fit. And they can't pop in.

[Guest]

Use some Threebond on them.

[rapidray]

Put them in backwards & you'll never have another problem! This is what we do to ALL of the dragbike & street engines with heads with the half moons. Ray.

[bwringer]

When installing a RealGasket, you have to use old half-moons -- the RealGasket is too soft to deform the new half-moons enough. If you threw out your old half-moons, you might need to use a regular valve cover gasket for a while or tr to find some old ones in "Parts Wanted".

Also, if you damaged your RealGasket, you over-torqued the bolts waaaaay too much. 15 inch-pounds is only 1.25 foot-pounds -- very little more than finger-tight. The RealGasket should get compressed by about 1/4 to 1/3 its thickness. I've had the same RealGasket for something like 60,000 miles -- they'll last a lifetime if you treat them right. And I've never lost a valve cover bolt.

And yeah, I usually install the half-moons backwards too. Works fine.

[loudest143]

Ladies and Gentlemen, the learned panel has spoken. Install the half moons in backwards, add a bit of silicone to the bottom rounded part, and move along.

Thanks for all the great (and prompt) responses!

loudest143