PISTON KIT YAM 350 R5 65.50, WOSSNER 8221D150

This piston kit is designed for Yamaha 350 R5 motorcycles manufactured between 1973 and 1975. It includes a single forged Wossner piston with a +1.50mm oversize (65.50mm bore), optimised for durability and performance in two-stroke engines. The elliptical design ensures uniform load distribution under heat expansion, reducing the likelihood of piston failure. Manufactured in Germany, this piston is engineered for reliability under demanding conditions.

Features

• Single forged Wossner piston

• +1.50mm oversized bore (65.50mm, actual piston diameter 65.43mm)

• Elliptical shape for even thrust load distribution and thermal stability

• Designed to optimise combustion heat transfer

• Made in Germany

Specifications

• Part Number: 8221D150

• Bore Size: 65.50mm (actual piston size 65.43mm)

• Oversize: +1.50mm

• Displacement: 347cm³

• Stroke: 54.00mm

• Clearance: 0.07mm

• Wossner Compression Ratio: 2-stroke

• OEM Compression Ratio: 2-stroke

• Compression Height: 36.00mm

Cross-Reference OEM Part Numbers

• Clips: CW16

• Piston Pin: WP027

• Rings: RSB6550 x 2

Vehicle Fitments

• Yamaha 350 R5 1973–1975