This Wossner piston kit is designed for Harley-Davidson Twin Cam engines upgraded to Big Bore configurations of 103 or 106 cu. in., covering model years 1999 to 2012. With a standard bore size of 3.934" and a compression ratio of 10:1, the kit includes two forged, domed pistons along with all necessary installation components. Manufactured in Germany, the pistons feature a design optimised for high performance, durability, and efficient heat dissipation.

Features

• Forged high-performance pistons with skirt coating

• Designed for optimal heat transfer from combustion chamber to cylinder walls

• Elliptical design provides consistent bearing surface under heat expansion

• Eliminates localised pressure and evenly distributes thrust loads

• Prevents piston collapse in high-stress operating conditions

• Includes pistons, rings, clips, and pins

Specifications

• Bore size: 3.934"

• Size: Standard

• Compression ratio: 10:1

• Dome type: Domed

• Quantity: Kit includes 2 pistons

• Country of manufacture: Germany

Cross-Reference OEM Part Numbers

• Wossner K8858DA-2

• 56-W9968.000.WO

Vehicle Fitments

• Harley-Davidson Twin Cam 88" Big Bore (103 cu. in.) 1999–2012

• Harley-Davidson Twin Cam Big Bore (106 cu. in.) 1999–2012