Piston kits & Components

An engine rebuild lives or dies on its pistons and rings, and this page lists them for Harley-Davidson Big Twin and Sportster engines. It includes stock replacement sizes, oversize sets and higher compression or forged options from three makers.

Makers and engines

Wiseco lists Tracker and EVO piston kits for Evolution engines, including 883/1200 sets at 9.5:1 compression. KB Pistons lists hypereutectic cast, forged alloy and Super Duty pistons for Twin Cam 88 to 95ci, Twin Cam 96 to 103ci, Milwaukee-Eight in 4.125 inch bore and Sportster 54ci, in compression ratios from 8.8:1 to 10.5:1 and oversizes such as .005, .010, .020 and .030. Hastings Mfg supplies cast iron and moly piston rings in standard and oversize for Evolution, Sportster, Twin Cam and Milwaukee-Eight engines.

Planning your build

Match engine displacement, bore size and compression to your cams and heads, because the piston is part of a system. Measure the cylinder, buy rings to match the piston, and plan on new base and head gaskets from gaskets and seals. Fuel-injected engines need a tune afterward. Also plan for oil, a new filter and a careful break-in procedure from the maker's instructions, because fresh rings need time to seat. Check valve clearances, cam timing and the condition of cylinder walls while the engine is apart. Performance engine parts are sold for off-road and closed-course use only.

For bigger builds, see the engine upgrades page.