I love cycling and recently purchased a new bike. My new bike is a Norco (Canadian bike) and is a lovely ride. My prior bike wasn’t as good and had a few unsightly decals (stickers) that needed removing.
 
With my experience in removing decals, I thought removing a decal from a bike would be easy. I was wrong.
 
Some bicycles (and motor bikes) have decals installed, then a lacquer / polish / varnish applied on top of it. What this means is the decal is sealed under the lacquer and it can not be removed off using a product like the Wonder Blade.
 
In this case you need to break / slice the lacquer so you can get to the decal, then peel the decal off (I used the Wonder Blade as it’s plastic so would scratch the painted surface – the Wonder Wheel is not suitable here).
 
Once the decal had been removed, I reapplied some lacquer to seal the surface. Often bicycles or petrol tanks (on motor bikes) use a lacquer to make the surface more shiny and also to seal the surface to avoid rust.
 
If you need to remove a decal from a bicycle or motor bike petrol tank that has a varnish or lacquer applied, then hopefully this insight has helped.