Has anyone seen this before?
Finally did a flush and fill (water wetter) on my bike. I noticed when I remove the original pressure cap that the paint in the middle was corroded off. Over the years I would get a very faint coolant odor but the reserve tank didn't show a noticeable drop. Long story short. I replaced the cap with a new one and look what I see after a 120 mile ride...and yes, I bled the water pump.
Cap on the right is the original.