AMSOIL Motorcycle Products: Something for Everyone Dirt Bike, V-Twin and Metric Oils fill out the AMSOIL Synthetic Motorcycle Oil line. With the introduction of several new and repackaged motorcycle products this year, AMSOIL offers something for every type of biker, from motocross racers and off-road riders to V-Twin and metric enthusiasts. AMSOIL motorcycle products deliver the power, performance and protection that every biker wants, no matter the motivation for getting on the bike. Dirt Bike To satisfy the demand for dirt-bike-specific oil, AMSOIL developed Synthetic Dirt Bike Oil in three viscosities, including 10W-40 (DB40) , 10W-50 (DB50) and 10W-60 (DB60) . AMSOIL Synthetic Dirt Bike Oil is designed to deliver consistent clutch feel and improve the performance of both bike and rider. Superior clutch consistency lets off-road (trail) riders expertly navigate trail obstacles without sacrificing momentum, helping them stay at the front of the pack. It also allo