Valve cover breather question GS1000

[Guest]

Hi - have run into something that I can't figure out (sigh...)...
My understanding it that the 2 small holes in the valve cover, leading up to the area under the breather cover, should always be open for the engine top to be able to breathe.
But on my GS1000 '81, these holes are closed with 2 screws and the holes are threaded to fit the screws - looking at exploded view diagram on cmsnl.com, there's no indication of any screws... But I can google images from restoration projects where these holes are plugged with screws similar to mine?!
So my question is really if these holes should be open or not - and if not, what's the idea of the breather function then?
I've attached an image from google for reference.

Thanks in advance
Kim
gs1000_engine_top_end_parts.jpg

[Rich82GS750TZ]

https://www.partshark.com/oemparts/a...ea18/cam-chain

Unintuitivey, you have to look at the cam chain fiche, not the cylinder head cover fiche.

The screws #7 hold the upper cam chain guide #6 to the underside of the valve cover. Turn the cover over and look underneath. They are supposed to be there.

[Guest]

Caught me being a bit lazy - should have flipped the cover first... ;-) Thanks for the swift reply - much appreciated!
Any chance that you might be able to explain the logic behind the cover breather function to me - with the two screws in place there are no open breather holes from the cam chamber?!

[Nessism]

Any chance that you might be able to explain the logic behind the cover breather function to me - with the two screws in place there are no open breather holes from the cam chamber?!

This is incorrect. There is lots of room for internal crankcase gasses to pass around the chain rub block and enter the breather cover.

[Guest]

My logic didn't make sense to me either ;-) Thanks for clarifying!!

[Steve]

Take a look at the picture you posted in the first post.

Those large openings that are sorta between the two red circles are the breathing passages for the system. There should be some metal mesh blocks in there, as well as in the mating area of the breather cover that covers that area. Four mesh blocks altogether. There is PLENTY of breathing area there, the hose that is in the cover will direct any blowby gasses back to the airbox, where they will get drawn into the airflow and through the carbs to be burned.

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