Brand New Race-Driven Piston Kit. You will receive 1 piston and assorted components to fit the following model: 1994 Yamaha VMAX 500 ST VX500ST. Race-driven pistons are designed to be a direct replacement for factory style pistons which closely match the original equipment in ring design and construction. These pistons have a hardened dome and a teflon coated skirt. All piston assemblies include rings, wrist pin and circlips. Race-Driven recommends the following preliminary work to be performed by a qualified mechanic prior to installing new pistons. If the old piston has failed, determine the cause and remedy the problem before replacing. Air leaks and/or a lean fuel mixture are the two biggest causes of burned pistons. In cases where any part of the old piston is broken or burned through, the crankcase should be disassembled and thoroughly flushed of any debris.