Back in Feb 05, I got a NOS Titan frame from the 80's that had very thin, fragile paint over chrome. Very pretty, but some paint had already dropped off in a few small spots. I did the whole frame with the old Rustoleum Clear and it has held up fairly well. The clear coat is chipped some, but the original paint & decals are still there.

My Torelli came clear coated over decals & frame from the factory. The Rustoleum on my Titan isn't as durable as the Italian stuff, but it has preserved the Titan's paint scheme pretty well. I have since successfully used Rustoleum clear to preserve old decals on other bikes and some of my old woodworking machines. Will take some pics & put them up later. Don