Wiseco Pistons 4939M08550 Compression ATV Piston Kit - 85.50mm 11 1

The Wiseco 4939M08550 is a high-performance forged piston kit engineered for demanding ATV applications. Featuring an 85.50mm bore and 11:1 compression ratio, this complete piston kit delivers enhanced power output and durability for Yamaha ATV engines.

Key Features:

• Forged in-house in the USA for superior strength and quality control
• 85.50mm bore diameter with 11:1 compression ratio for optimized performance
• Condensed grain structure aligned to part features for maximum impact and fatigue resistance
• Engineered strength-to-weight ratio maximizes performance without excess weight
• 19.5mm wrist pin design for precise fitment
• Complete piston kit includes piston, rings, wrist pin, and circlips

Applications:

• Yamaha YFM450 Grizzly (2007-2009)
• Yamaha YFZ450 Rhino (2006-2009)
• Yamaha YFM450 Kodiak (2003-2006)
• Yamaha YFM450 Wolverine (2006-2009)

Wiseco's forging process creates a denser, more durable piston compared to cast alternatives. The aligned grain structure provides exceptional resistance to the extreme heat and stress of high-performance motorsport use, while the precise machining ensures reliable performance and long service life.