Wiseco 4487M07800 Forged Piston Kit Bore Compression Yamaha - 78.00mm 12 1 FZR1000 YZF1000

The Wiseco 4487M07800 is a high-performance forged piston kit featuring a 78.00mm bore (2.50mm oversize) and 12:1 compression ratio, purpose-built for the Yamaha FZR1000 and YZF1000 inline-four engine. Each kit is engineered, forged, and machined in the USA at Wiseco's facility in Mentor, Ohio, and designed to deliver an optimized combination of strength, light weight, and precision fit for high-performance street and track applications.

Wiseco uses dedicated forgings for each specific engine application — meaning this piston is not adapted from a generic blank but designed from the ground up for this bore and application. The high-silicon, low-expansion aluminum alloy construction provides superior tensile strength, reduced weight versus cast pistons, improved heat transfer, and extended service life under hard use.

Key Features:

• Bore Size: 78.00mm (2.50mm oversize)
• Compression Ratio: 12:1
• Material: Forged high-silicon, low-expansion aluminum alloy
• Dedicated forging designed specifically for this engine application
• Optimized strength-to-weight ratio for maximum horsepower and torque
• Diamond-turned CNC finish for precise sizing and no variation
• Compatible with cast iron, chrome, Nikasil, and boron composite cylinder bore compositions
• Kit includes: Piston, rings, wrist pin, and circlips
• Engineered, forged, and machined in the USA (Mentor, OH)

Important: This is an oversize piston. Oversize pistons require cylinder sleeving or professional bore matching. The Wiseco R1070 cross-reference designates this as part of the top-end kit lineup for this application.