Wiseco PK1273 Top End Piston Kit 53.5mm 0.50mm Oversize 9.4:1 CR

The Wiseco PK1273 is a complete top end piston kit designed as a 0.50mm oversize rebuild solution delivering a 53.5mm actual bore diameter and a 9.4:1 compression ratio. This kit is engineered from aerospace-grade forged aluminum alloy, offering an exceptional strength-to-weight ratio that surpasses OEM cast piston performance.

Each kit is precision machined on state-of-the-art CNC equipment using the same low-expansion, low-friction alloy found in major Japanese OEM engines — ensuring tight tolerances, reduced heat buildup, and extended service life. The dedicated forging process and optimized cam profile deliver peak horsepower output while maintaining long-term durability.

Kit Includes:

• Forged piston — aerospace alloy, CNC machined to 53.47mm piston diameter (53.5mm bore)
• High-performance piston ring set — extended life rings for sustained power and sealing integrity
• Alloy wrist pin — precision ground for consistent fit and reduced friction
• Circlips — retaining clips included for complete assembly
• Wiseco top end gasket kit — premium materials exceeding OEM sealing standards

Key Specifications:

• Bore Size: 53.5mm (0.50mm oversize)
• Piston Diameter: 53.47mm
• Compression Ratio: 9.4:1
• Stroke: 45mm
• Displacement: 99.2cc
• Forging Code: 4666M
• UPC: 193564153906

Important: Wiseco pistons are designed to be used exclusively with Wiseco rings. Wiseco ring types are not interchangeable between piston series. Cylinder boring to 53.5mm is required prior to installation.