Cam Shaft Cover Gasket

[RC]

My cam shaft cover gasket looks to be leaking slightly, so that will get replaced.  At the same time I'll have the valve clearance checked.

On the gasket there are two semicircular platic things covered in rubber.
You can see them on the bike off course, but they really stand out when your just looking at the gasket.

What's up with that? What is that plastic thing supposed to do?

Sorry if "plastic thing" is not the exact technical terminology.

Ron

[KevinC]

That fills the cut-out in the head where the cam bearings were line bored.