The Wossner 8724DA forged piston kit with a 74.00mm bore is designed for Yamaha YFM250R Raptor (2008–2013) and YBR250 (2008–2012). Manufactured in Germany, this high-compression piston enhances strength and heat transfer performance. Its elliptical shape ensures even pressure distribution during thermal expansion, reducing the risk of piston failure.

Features

• Forged high-compression piston for durability and performance


• Engineered for efficient heat transfer to cylinder walls


• Elliptical design ensures uniform pressure distribution during heat expansion


• Reduces localized stress and risk of piston collapse


• Manufactured in Germany

Specifications

• Bore: 74.00 mm


• Actual Bore Diameter: 73.95 mm


• Hub Stroke: 58.00 mm


• Clearance: 0.05 mm


• Compression Height: 23.50 mm


• Dome Volume: +2.40 cm³


• Wossner Compression Ratio: 12.00:1


• OEM Compression Ratio: 9.50:1

Cross-Reference OEM Part Numbers

• Piston: 8724DA


• Lock: CW17


• Pin: WP083


• Ring Set: 740XDS


• Part No.: 56-W4950.A.WO


• OEM Reference: 1S4-11631-20-A0, 40078M07400

Vehicle Fitments

• Yamaha YFM250R Raptor 2008–2013


• Yamaha YBR250 2008–2012