Wiseco 4755M09800 4-Stroke Forged Piston Kit 98mm +2mm Overbore 12.5:1 Compression

The Wiseco 4755M09800 is a high-performance forged 4-stroke piston kit designed for Honda CRF450R and CRF450X engines. Featuring a 98.00mm bore diameter (+2mm oversize), a 12.5:1 compression ratio, and a -1.2cc domed piston design, this kit delivers the increased compression and power output serious motocross and off-road riders demand.

ArmorGlide Skirt Coating: This piston features Wiseco's proprietary ArmorGlide skirt coating — the result of extensive in-house dyno testing and development. ArmorGlide reduces piston-to-bore friction, allows for tighter piston-to-wall clearance for improved ring seal, and minimizes piston rock and noise, all while maximizing horsepower output and wear resistance.

Key Features:

• Bore Size: 98.00mm (+2.00mm oversize)
• Compression Ratio: 12.5:1 high compression
• Dome: -1.2cc domed piston design
• Forged from high-silicon, low-expansion aerospace aluminum alloy for superior strength, reduced weight, and improved heat transfer
• ArmorGlide skirt coating reduces friction and contributes to increased horsepower and longevity
• Dedicated application-specific forging optimizes strength-to-weight ratio
• CNC diamond-turned finish ensures precise sizing with zero variation
• Engineered, forged, and machined in the USA (Mentor, OH)
• Kit includes: Piston, high-performance ring set, wrist pin, and circlips

Important Installation Note: This +2mm oversize piston requires professional cylinder boring and Nikasil replating or installation of a new cylinder sleeve prior to use. It is not a drop-in replacement for a standard bore cylinder.