Engine

Active filters
Includes top and second compression rings plus three-piece oil control rings; supplies enough rings for two pistons for reliable sealing and oil control.
Complete replacement ring set with top and second compression rings plus three-piece oil control rings. Restores compression, controls oil, and improves oil economy. Includes enough rings for two pistons. Made in the USA.
Complete set of top, second, and three-piece oil control rings for two pistons. Barrel face top rings and Napier second rings provide improved sealing and heat transfer; three-piece Flex Vent oil rings ensure positive oil control. Made in the USA.
Complete replacement piston ring set with PVD coating: barrel face top rings, Napier second rings, and three‑piece flex vent oil control rings. Includes enough rings for two pistons.
State-of-the-art compression release valves that reduce hot starts and lower starter and battery loads. Sold as a set and made in the U.S.A.
State-of-the-art design to reduce hot starts and starter/battery loads. Custom molded knobs, sold in pairs, made in the U.S.A.
Designed for HD® Evolution OEM replacement. Machined from high‑grade metal with a corrosion‑resistant dark finish. Multipurpose alignment pins. Made in the USA.
PTFE valve guide seals with twin-spring tension for reduced friction and reliable valve control. Made in USA.