PISTON KIT 99-18 YZ250 1-RING, WOSSNER 8217DB 66.40

This Wossner piston kit with a 66.41mm bore (+0.01mm oversize, actual size 66.36mm) is specifically designed for Yamaha YZ250 models from 1999 to 2018. Featuring a single-ring forged design, it delivers reduced friction, reliable performance, and durability under the demands of two-stroke operation.

Features

• Forged single-ring piston enhances response and reduces friction

• Engineered for optimal heat transfer from the combustion chamber to cylinder walls

• Elliptical design distributes load evenly and prevents piston collapse during thermal expansion

• Manufactured in Germany for high precision and reliability

Specifications

• Bore size: 66.41 mm

• Actual piston size: 66.36 mm

• Display (cm³): 249

• Stroke (mm): 68.00

• Clearance (mm): 0.05

• Compression ratio: 2-stroke (Wossner and OEM)

• Compression height (mm): 38.00

Cross-Reference OEM Part Numbers

• OLD No. 56-W056.WO.B

Vehicle Fitments

• 1999–2018 Yamaha YZ250

Included Components

• Piston: Wossner PN# 8217DB (Single ring)

• Gasket: PN# D2041

• Lock: PN# CW18

• Pin: PN# WP033

• Ring Set: PN# RSB6640

• Rod: PN# P2028