Piston Kit 99-18 YZ250 66.40 a, Wossner 8216DA Yamaha MX, 2 Ring Piston

This Wossner piston kit with a 66.40mm bore (actual size 66.35mm) is engineered for Yamaha YZ250 models from 1999 to 2018. Designed and manufactured in Germany, the forged piston provides superior strength, efficient heat transfer, and reliable performance in two-stroke applications.

Features

• Forged construction for high durability and mechanical strength

• Optimised for combustion chamber heat transfer to cylinder walls

• Elliptical design ensures even load distribution and reduces risk of piston collapse

• Precision-manufactured in Germany

Specifications

• Bore size: 66.40 mm

• Actual piston size: 66.35 mm

• Display (cm³): 249

• Stroke (mm): 54.10

• Clearance (mm): 0.06

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

• Compression height (mm): 28.00

Cross-Reference OEM Part Numbers

• 1P8-11631-00-A0

• 1P8-11631-00-B0

• 1P8-11631-00-C0

• 1P8-11631-00-D0

• 5CU-11603-10-00

• 5UP-11633-00-00

• 93450-19052-00

Vehicle Fitments

• 1999–2018 Yamaha YZ250

Included Components

• Piston: Wossner PN# 8216DA (2-ring)

• Lock: PN# CW18

• Pin: PN# WP033

• Ring Set: PN# RSB6640 x 2

• Rod: PN# P2028