I bought the tank at a shop that sold mini bikes and pocket bikes the tank was 35$'s it was off a bike that some kid wrecked but they also sell them on e bay under mini chopper gas tanks. Mounting them is a little tricky but once you learn how it is easy they usualy hold about 2.5 gal or 3 gal. and what is amazing is they baffel the sound of the motor a little.
The blue bike is the one that won we are now working on the red one it is a little odd to peddel but it should have alll the little quriks worked out soon we have never done one of these choppers befor and have had to fabricate a lot on it but it is pretty.
Joe thanks for posting those pic my puter is so slow I could not get the pic in photo bucket.
PS I have a Savanna cat that looks a lot like this one