Wiseco 839M05300 Forged ATV Piston Kit 53mm 1mm Overbore 2-Stroke

The Wiseco 839M05300 is a high-performance forged 2-stroke ATV piston kit with a 53.00mm bore, representing a 1.00mm overbore over the standard cylinder dimension. Forged from high-silicon, low-expansion aluminum alloy, this piston delivers superior strength, reduced weight, improved heat transfer, and extended service life compared to stock cast pistons.

Wiseco is the only aftermarket piston manufacturer in the United States that produces pistons strictly using the forging process. Starting with aerospace-grade aluminum, the forging process compresses the material's molecules, increasing alloy density and aligning grain flow — resulting in a piston that is highly resistant to impact, fatigue, and tensile strain. Each piston is finish-machined on CNC turning centers for a precise, consistent fit with no size variation.

Kit Includes:

• Forged 2-stroke piston (53.00mm bore)
• Piston ring(s)
• Circlip: CW18

Key Specifications:

• Bore Size: 53.00mm
• Oversize: 1.00mm overbore
• Engine Type: 2-Stroke
• Wiseco MPN: 839M05300
• Compatible Circlip: CW18
• Compatible Wrist Pins: S393, S257, S511, S508

Important Notes:

• Only Wiseco replacement ring sets are compatible with Wiseco pistons.
• Wrist pin is not included unless specifically noted — order separately if required for your rebuild.
• Compatible with cast iron, chrome, Nikasil, and boron composite cylinder bore compositions.

Wiseco's oversize piston options are ideal for restoring worn cylinder bores in cast iron-lined cylinders, and with the availability of replacement cylinder sleeves, Nikasil and boron composite cylinders can be re-sleeved to accept Wiseco oversize pistons. Engineered, forged, and machined in Mentor, OH, USA.