PISTON KIT 99-18 YZ250 66.40 C, WOSSNER 8216DC YAMAHA MX, 2 RING PISTON

This Wossner piston kit with a 66.42mm bore (+0.02mm oversize, actual size 66.37mm) is designed for Yamaha YZ250 models from 1999 to 2018. Featuring a forged 2-ring design, it delivers enhanced durability, heat dissipation, and reliability under high-performance two-stroke engine conditions.

Features

• Forged 2-ring piston for strength and long-lasting performance

• Optimised for effective heat transfer from the combustion chamber to the cylinder wall

• Elliptical profile distributes load evenly, reducing localised pressure and risk of piston collapse

• Precision-engineered and manufactured in Germany

Specifications

• Bore size: 66.42 mm

• Actual piston size: 66.37 mm

• Display (cm³): 249

• Stroke (mm): 54.10

• Clearance (mm): 0.06

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

• Compression height (mm): 28.00

Vehicle Fitments

• 1999–2018 Yamaha YZ250

Included Components

• Piston: Wossner PN# 8216DC (2-ring)

• Lock: PN# CW18

• Pin: PN# WP033

• Ring Set: PN# RSB6640 x 2

• Rod: PN# P2028