A leak somewhere ?

Coming from cap? There looks to be the same grime on left side which makes me think its not a leak just dirty. Anyone else have any idea? Can't notice oil anywhere, like on exhausts etc.
 
Check your rear cylinder cam cover gasket. Mine has leaked twice already. Look for oil going down the back, front, or sides of the gasket. Otherwise, looks like your O-Ring is leaking a little maybe. hopefully there aren't any fine cracks in your engine casing.
 
There actually looks like cracks on it but maybe that's how it's meant to look? It's no sign of leak from the cracks so I doubt it. Is it know to leak from the o ring ?
 
What I was wondering is if there is a crack in the casing, your rear cylinder gasket, or your clutch cover gasket. check for leaks where the clutch cover meets the engine case.
 
Thing is I don't see any leaks in the picture. It just looks like dust and dirt have collected on the leftover oil when they filled it. Even if they wipe it off it's still going to be dirty there. But as for the O-Ring it should have no cracks in it at all. It probably dry rotted after sitting for a while and if so, would be the cause of your small leak.