Race-Driven Piston Rings. You will receive 2 pairs of piston rings to fit the following model: 1998 1999 Ski-Doo MXZ 500 L/C. Race-driven piston rings are designed to be a direct replacement for factory style rings which closely match the original equipment. Rings may not work on other aftermarket pistons. 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. Race-Driven is committed to bringing the highest quality products to all riders at an affordable price.