not sure what material your new badges are ........here is a tip warm up the tank by leaving it inside the house overnight and also the badges, they will be more pliable and the adhesive will work better. Remember, that not adhesives will stick to all surfaces so be careful with that. Also is your tank palstic or metal, some adhesives will eat through plastic tanks.
I purchased new sidepanel decals and put them on my tank under the DUCATI that it came with from the factory.
I don't have side panels anymore ,but loved that little aluminum decal, so to be different I put it on my tank.