The only 'Kart' tank I've ever really know of is the ones they use in most Go-Karts. Not sure on the size, it's about 2 gallons, and I personally like it. More room to make wrenching easier and it holds less fuel than stock, which is good and bad. Good because it's less weight, and bad because you have to fill up. My XS BOB came with a JAZ fuel tank, and i'm certain that it's more than 2 gallons, and it's real nice, but I like the original Kart Tank more.