Wiseco 603M05650 Forged Piston Kit Bore Oversize - 2-Stroke 56.50mm 0.50mm

The Wiseco 603M05650 is a forged 2-stroke piston kit with a 56.50mm bore diameter, representing a +0.50mm (0.020") oversize over the standard 56.00mm bore. Designed for dirt bike engines, this kit delivers the strength and precision needed for top-end rebuilds and engine restorations demanding reliable performance under high-RPM, high-heat conditions.

Wiseco pistons are manufactured exclusively using the forging process — the only major U.S. aftermarket piston brand to do so. Each piston is forged from high-silicon, low-expansion aluminum alloy and diamond-turned on CNC machining centers for consistent sizing and a precision fit. This construction yields a superior strength-to-weight ratio, improved heat transfer, and extended service life compared to cast alternatives.

Kit Includes:

• 1x Wiseco 603M05650 forged piston — 56.50mm bore
• 1x Wiseco 2224CS piston ring set — 56.50mm
• 1x Wiseco S514 wrist pin — 16.0mm
• Circlips

Key Specifications:

• Bore Diameter: 56.50mm
• Oversize: +0.50mm / +0.020"
• Standard Bore Reference: 56.00mm
• Wrist Pin Diameter: 16.0mm
• Engine Type: 2-Stroke
• Ring Set Part Number: 2224CS
• Wrist Pin Part Number: S514

Important: Only Wiseco replacement ring sets are compatible with Wiseco pistons. Wrist pin is included with this kit. This piston is compatible with cast iron, chrome, Nikasil, and boron composite cylinder bore compositions.