Wiseco WK1321 2-Stroke Watercraft Complete Forged Piston Kit with Top-End Gasket Kit

The Wiseco WK1321 is a complete 2-stroke watercraft piston kit engineered for high-performance personal watercraft applications. Each kit includes a high-performance forged piston, rings, wrist pin, circlips, and a top-end gasket kit — everything needed for a full top-end rebuild in one package.

Forged Construction:

• Pistons are forged from high-silicon, low-expansion aluminum alloy for superior strength and reduced weight
• Forged grain structure is aligned to part geometry, delivering higher mechanical properties and resistance to impact and fatigue compared to cast alternatives
• Improved heat transfer properties extend overall piston service life

Precision CNC Machining:

• Diamond-turned finish from CNC turning centers ensures a perfect, consistent bore size with no dimensional variation
• Compatible with all modern cylinder bore compositions including cast iron, chrome, nikasil, and boron composite
• All forge tooling is produced in-house, allowing full control of the manufacturing process from raw bar stock to finished skirt-coated parts

Oversize Availability:

• Available in a range of oversize options to extend the service life of cast iron lined cylinders
• Chrome, nikasil, and boron composite cylinders can be resleeved to accept Wiseco oversize pistons
• Oversize pistons require cylinder boring prior to installation

Kit Includes:

• High-performance forged piston
• Piston ring set
• Wrist pin
• Circlips
• Top-end gasket kit

Wiseco is the only U.S. aftermarket manufacturer that forges all of its own pistons in-house at its facility in Mentor, OH. In-house dyno testing and finite element modeling software are used throughout development to ensure each piston delivers the optimal strength-to-weight ratio for its specific application. Note: Wiseco rings are application-specific and are not interchangeable between ring types — use only Wiseco rings with Wiseco pistons.