I want to remove the decals from my bike

The older the bike, the harder it is to remove the decals. On new bikes they will peel right off. On older bikes a hair dryer or heat gun will help soften the sticker. Be patient and re-apply heat as needed. Most likely it will leave some glue residue. WD-40, Goo-Gone or turpentine will help remove the residue. Follow with a good coat of cleaner/wax.

About the tank: If you're trying to take the decals off the tank, be aware that they're underneath the paint's clear coat and are not going to come off without a fight. Your options are:

• Sand the clear coat off over the decal, remove the decal, try to touch up the paint, then reapply clear coat. Will probably end up looking much worse than whatever decal you were trying to remove in the first place.
• Repaint the entire tank. See the Painting section of Bodywork & Frame.
• Get a bigger sticker and put it over the one that's there. This has the advantage of being able to change it from time to time.