Wiseco 6650M865 Honda K-Series Dome Forged Piston Bore - 10.5cc 86.5mm

The Wiseco 6650M865 is a Professional Series forged piston engineered for Honda K-Series engines. Featuring a +10.5cc dome crown, 86.5mm bore, and 1.181-inch (30mm) compression height, this piston is purpose-built to support high compression, forced induction, and high-RPM race builds on the K20A and compatible K-Series platforms.

Wiseco's Professional Series represents their highest tier of performance piston construction — designed for serious racers and engine builders who demand custom-level quality from a shelf-stock part. The dome profile is ideal for achieving elevated compression ratios in naturally aspirated builds seeking maximum power output.

Key Features:

• +10.5cc Dome Crown — designed to increase compression ratio for high-performance naturally aspirated applications
• 86.5mm Bore Diameter — fits standard and lightly overbored Honda K-Series cylinder bores
• 1.181" (30mm) Compression Height — compatible with stock and aftermarket connecting rods
• 2618 Forged Aluminum Construction — superior tensile strength and resilience under extreme heat and high-RPM stress
• ArmorGlide® Skirt Coating — reduces friction, resists seizures, and contributes to quieter operation
• Fully Machined Crown — precision ring grooves, anti-detonation groove, and enhanced ring seal technology
• 0.866" (22mm) Wrist Pin Diameter — compatible with OEM and aftermarket K-Series floating pin setups
• Engineered, forged, and machined in the USA

Sold as a single piston. Wiseco's Professional Series is the go-to choice for Sport Compact engine builders competing in demanding race environments where reliability and performance cannot be compromised.