If you lift up the edge of the sticker, and get some petrol on a cloth, and dab it around. it should peel of. If you don't have any spare petrol, WD-40 will do. But doing this can make the paint on your frame bubble. Otherwise, get a hairdryer and keep it on the sticker, Which makes the glue soften up. So it's a hell of a lot easier to peel off. Or reverse effect, if you warm up the frame if you get new stickers it makes the sticker stick 10 times better.