Evening everyone, Just took the spark plug from my bike (1965 B40F) and noticed something - don't know how I've not noticed it before, must have had my eyes closed. Please see attached photos. At the edge of the machined seating for the spark plug are what look to me like two holes, areas of porosity? Any comments/explanation please? I was a bit concerned when I saw them. Should I be? Thanks as always in advance. Phil.
I think they just go between the head fins.
I agree, looks like the way it came out of the casting. Possibly not machined deep enough, but looks fine.