Harley-Davidson SPORTSTER 1200 CUSTOM Big Bore Kits

Genuine Harley-Davidson

CNC Ported Heads offer a cost-effective approach to upgrading the performance of your motorcycle. The intake and exhaust ports are meticulously machined for smooth surfaces, improving the flow characteristics of air and fuel in order to provide enhanced performance. But it doesn't end there: the proven stock valves rest in reshaped valve seats to further improve flow rates. The combustion chambers have been machined for smooth surfaces and feature a blended radius on the bathtub edge to reduce detonation by eliminating hot spots and promoting improved combustion. The head gasket surface has been milled to maintain stock combustion chamber volume (59.9cc), which results in stock compression when used with Original Equipment pistons. Compression can be increased with the installation of Screamin' Eagle high-compression pistons. Heads are assembled with Original Equipment valves and high-performance valve springs that support cams with lift up to.585". All EFI models require ECM calibration (priced separately). For race application only.

Genuine Harley-Davidson

Designed to develop a 10.5:1 compression ratio when combined with stock heads, or 11.3:1 ratio when combined with Screamin' Eagle Performance Heads P/N 16677-07 or 16677-05. These forged pistons have been plated with electroless-nickel for maximum durability in high-performance applications. Kit includes a pair of pistons, wrist pins, rings and circlips.