Thank you Ian,
And I will definitely check the article on the tech' part.

Michiel, thanks for the advice.

Actually I dipped my finder in the bike's oil tank and smeared oil
Over the 2 sides of the cork gasket.
As far as I can see now, after a week or so- all is well. no drip.

Generally, where sealant is needed, I do not use silicone on the bike.
I am a great fan of Shellac. I use "ABRD" Eagle Shellac.
I like it better than silicone. it's very sticky,(Try to get it of your hands...)
thinner then RTV/silicone in texture, and it does not tens to tear off and get into your oil circulation
Or anywhere else, if you have a build up of an access material in the cases..

Cheers,
Noam.