I was struck by how black and oily these valves were on the up side and how very white they were on the combustion chamber side! Usually, the exhaust valve is just like  these, but the intake should be clean metal or a light crust of beige unburnt hydrocarbon residue. I think this old Harley has been running a little too lean for quite some time!

1993 Harley Davidson FLHT-C

This pic made me think of Mooneyes…