Can anyone suggest where this oil stain may have come from before I take my bike to a dealer? I think it might be from the rear cylinder head gasket, but not too sure. It appeared recently...
Looking at the photos what looks like drops of liquid are on the second and third fins from the top lower rocker gasket blown would also be on the top fin head gasket would be much lower down the engine
Clean off with a degreaser gunk would be my choice and keep an eye on to see if it appears again
I agree clean it off and go to a good auto parts store and get some glow in the dark(black light) oil additive that will tell the tail of the leak.
good luck