Oil leak near left-most spark plug

[Crabbypants15]

My bike is a 78 gs750 and there's a small oil leak around my left most spark plug when running the bike. I replaced all plugs yesterday but the leak persists so I figure it's not coming from them. I tried uploading a picture but it failed. Does anyone know what it could be? Thank you.

[Nessism]

Maybe the valve cover gasket or from around one of the outside studs, which are oil passages.

Standard procedure is to degrease the engine, dry it off, start engine and look for source of leak. Some guys like to spray foot powder on the area because the white appearance will make any oil stain quickly standout.