This is what happens when any of the valves are open when you leave an engine sitting for years and years... The air is allowed to enter the combustion chamber which promotes rust. It's pretty obvious here that there is much more rust in the side that has the open intake valve. Thank goodness that the exhaust valves weren't open! Yet air still comes in and out of the intake side nonetheless. So the next time you store your bike for over two decades make sure and plug the exhaust and intake up with rubber balls. :P
Now the cylinder head rust isn't that big of a deal to me. I'll be taking the valves out and lapping the seats anyways. Besides the valve seats getting a little gritty from rust (totally fixable) the rust is basically just cosmetic. But the cylinders getting rusty is a HUGE problem. Keep onnnn readin...