AMSOIL Synthetic V-Twin Primary Fluid is purpose-built for bikers who prefer a dedicated primary chaincase lubricant. AMSOIL V-Twin Synthetic Primary Fluid is purpose-built for bikers who prefer a dedicated primary chaincase lubricant. Its balanced formulation delivers consistent clutch feel for confident takeoffs, helping riders avoid killing the engine. It also protects components against wear to help riders get the most out of their bikes. V-Twin Synthetic Primary Fluid is Warranty Secure™ and will not void your motorcycle's warranty. It is a cost-effective, high-performance alternative to original equipment manufacturer (OEM) fluids.