This Wossner piston kit is designed for Harley-Davidson Twin Cam 88" engines that have been upgraded to a Big Bore 103 cu. in. configuration. With a bore size of 3.872" (+0.005" oversize) and a compression ratio of 10:1, this forged piston set ensures optimal performance, heat dissipation, and durability under high-stress conditions. Manufactured in Germany, this kit includes two pistons along with rings, clips, and pins for complete installation.

Features

• Forged high-performance pistons with skirt coating

• Engineered for improved combustion heat transfer to cylinder walls

• Elliptically designed to provide uniform bearing surface under heat expansion

• Helps eliminate localised pressure and evenly distribute thrust loads

• Prevents piston collapse under thermal stress

• Includes pistons, rings, clips, and pins

Specifications

• Bore size: 3.872"

• Oversize: +0.005"

• Compression ratio: 10:1

• Dome type: Domed

• Quantity: Kit includes 2 pistons

• Country of manufacture: Germany

Cross-Reference OEM Part Numbers

• Wossner K8857D015-2

• 56-W9967.015.WOO

Vehicle Fitments

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