I am thinking about making a prototype Kevlar/ Carbon fiber gas tank for the WR/yz 450. The stock wr tank is just over 5 lbs dry. I 'm thinking mine will weigh around 2 lbs and will be roughly 2-3 gal. capacity. It will carry the gas really low on the bike for an extremely low center of gravity. I will also be redoing the airbox out of carbon fiber, getting a custom air filter, and moving the air filter up to where the battery used to be. Below the air filter I will put an auxiliary fuel tank of around 1/2 to 3/4 gal. It will use a small 12 v fuel pump to pump the fuel into the main tank when it is low. This setup should be extremely versatile. For long rides full fuel capacity could be around 4 gal. For track riding or short rides I would only run 1 gal that would be carried as low as possible ( but still above the carbeurator) for a really light feeling bike. The most important thing is to carry the fuel as low as possible on the bike. I think this is a good idea but would like to hear other peoples opinions and ideas. I am always looking to improve things and build new things. You never know what you'll come up with.