I'm super late to the party but the best penetrating oil I've ever used (& I think I've tried most of them) is Aerokroil. Marvel Mystery is good, PB Blaster is good, and my grandfather used 3 in 1 on everything when I was a kid, so I trust it too. But Aerokroil is the best. Lots of folks just call it Kroil, orange spray can comes out red, very much like a slicker tranny oil. I use it with a needle dropper on rusty saddle screws on guitars too. It's the only stuff that's worked for me there...
Oh and... What's up with this bike?
Carl.