WOSSNER 77mm PISTON KIT A, YAMAHA YZ250F 14-15, WR250F 15-17, YZ250FX 15-16

This Wossner forged piston kit, part number 8893DA, features a standard 77mm bore with an actual piston size of 76.96mm. It is engineered for TM MX-F450 (2009–2010), MX-Fi450 (2011), and EN-Fi450 (2011) models. Manufactured in Germany, the piston is designed for high-performance four-stroke applications, offering superior heat transfer, strength, and pressure distribution due to its elliptical profile.

Features

• Forged construction for strength and long-lasting durability
• Elliptical design for uniform expansion and thrust load balance
• Optimized for heat transfer in high-performance engines
• Made in Germany
• Direct OEM replacement
• Easy to install; professional installation recommended if unsure

Specifications

• Bore Size: 77.00mm
• Actual Piston Size: 76.96mm
• Displacement: 249cm³
• Stroke: 53.60mm
• Clearance: 0.05mm
• Dome Volume: -3.00cm³
• Wossner Compression Ratio: 13.70:1
• OEM Compression Ratio: 13.50:1
• Compression Height: 20.20mm

Cross-Reference OEM Part Numbers

• 40116M07700
• 1SM-11631-01-00
• CW16 (Lock)
• WP087 (Pin)
• 770XAS-2 (Ring Set)

Vehicle Fitments

• TM MX-F450 (2009–2010)
• TM MX-Fi450 (2011)
• TM EN-Fi450 (2011)

Majority of our listings are for a direct replacement for your original part.

Our parts are made of quality and are designed to meet or exceed the original OEM Standards.

Our products are often a cost effective alternative to genuine OEM Parts.

Please note: the models of bike we state in our listings are for general guidance only. Please make sure this item will fit your bike before purchasing. Also, we cannot guarantee fitment to any non-UK models.