It is neither difficult nor expensive to replace your ATV's old gas tank. Here is a fuel tank for the 90cc Baja Canyon and Wilderness Trail ATVs that installs in a flash.
As well as the Baja models, this black plastic 3.08-liter capacity gas tank fits numerous Chinese ATVs or quads in the 50cc to 125cc range. Some of the compatible brands include Sunl, Coolster, Roketa, and TaoTao.