I've taken badges and emblems off several bikes using 8 lb fishing line and WD-40, ONE CAUTION, do NOT use a fast sawing motion when using the line, it can generate friction and damage the paint. Slow and steady works, I spray the WD over top and let it soak in a bit, then start with the string. The best stuff I ever used to take off the remaining sticky was 3M wax and adhesive remover but for some reason 3M just discontinued that product. Check with your local auto paint store and see what they suggest to remove sticky with no paint damage. I have used Lacquer thinner as well.
Heat and fishing line along with a second set of hands. Take the gas cap off in a well ventilated area. Take a good hair dryer (shouldn't need a heat gun for this) and heat the area where the emblem is. While gently pulling the emblem away from the tank, use the fishing line like dental floss to get between the glue and the paint. Now I used this on a white bike which was pretty forgiving as far as marks go but I think this is the safest way. Don't be in a hurry. I also used goo-gone with no damage to the paint. Only goo-gone though...... Hope this helps....
You're going to be heating gasoline in an enclosed space. Not "sure" it's necessary but I'd rather not have pressure building up in the tank from an accidently overheated tank. I know it does in the sun and it's vented but still......