U4.4™ If you’re not bound by fuel rules, this leaded fuel is the best choice for virtually any powersports application, offering the biggest gain vs. cost of any performance part you can buy. The latest generation of our U4-based fuels, U4.4 makes up to 6% more power than pump gas across a wider range of applications than its predecessors. It yields no sticky residue and is more resistant to heat. Designed as a direct, pour-in replacement for pump gas, it will require modest jetting changes, i.e., +2 main jets or +2 pilot jets at most. With its higher octane rating, U4.4 is designed for use in stock and modified 2-stroke and 4-stroke applications. U4.4 passes fuel rules for AMA Pro/Am, CCS, WERA, AFM, NMA, WORCS, SCORE and Best in the Desert as well as club level racing and more.