Hi in new to the forum and was wondering if anyone can help me out, I have a baba doodle bug that I'm fixing up, also gonna make it a trike with big knobby tires, but that's no the point I need a gas tank that is small and will fit on the bike. All the tanks I want are 50-100$ because they're spun steel or aluminum, are there any similar types of tanks even plastic tanks that are the same size and shape?