Wiseco R1186 Big Bore Forged Piston Kit 80mm 2.00mm OS 12:1 Compression

The Wiseco R1186 is a complete big bore forged piston kit designed as a performance top-end rebuild solution. Featuring an 80.00mm bore diameter — a 2.00mm oversize over the standard 78.00mm bore — and a 12:1 compression ratio, this kit delivers the power and durability demanded by high-performance street and drag bike applications.

Key Features:

• Forged High-Silicon Aluminum Construction: Each piston is precision-forged from high-silicon, low-expansion aluminum alloy, providing superior tensile strength, reduced reciprocating weight, and improved heat dissipation compared to cast alternatives.
• Diamond-Turned CNC Finish: Machined on state-of-the-art CNC turning centers, every piston receives a diamond-turned surface finish that guarantees consistent sizing with zero variation — ensuring proper fit and reliable sealing in the bore.
• Compatible with All Cylinder Bore Compositions: Wiseco's tight tolerances and precision finish make the R1186 compatible with cast iron, chrome, Nikasil, and boron composite cylinder bores, offering flexibility for engine builders and rebuilders.
• 2.00mm Oversize for Cylinder Restoration: The oversize bore specification extends the service life of worn cylinders. Cast iron lined cylinders can be bored directly to accept this piston; chrome, Nikasil, and boron composite cylinders can be re-sleeved to the appropriate oversize.
• Complete Kit: Includes pistons, piston rings, wrist pin, and circlips — everything needed for a full top-end rebuild.

Kit Specifications:

• Bore Diameter: 80.00mm
• Oversize: +2.00mm (standard bore: 78.00mm)
• Compression Ratio: 12:1

Built to the same exacting standards Wiseco has applied to forged pistons for decades, the R1186 is an ideal choice for enthusiasts performing an oversize bore rebuild or seeking a high-compression performance upgrade.