Wiseco SK1243 2-Stroke Piston Kit for Ski-Doo 494 Twin Liquid 69.50mm Bore

The Wiseco SK1243 is a complete Pro-Lite forged 2-stroke piston kit designed for Ski-Doo 494cc twin-cylinder liquid-cooled snowmobile engines. Built to a standard bore of 69.50mm, this kit delivers the strength, precision, and reliability demanded by snocross and cross-country snowmobile applications.

What's Included:

• Forged Pro-Lite piston(s)
• Piston rings (matched to Wiseco forged pistons)
• Wrist pins (18mm, non-chromed)
• Circlips (round wire, 18mm)
• Top-end gasket set

Key Specifications:

• Bore: 69.50mm (Standard)
• Stroke: 65.80mm
• Displacement: 499cc
• Cylinders: 2
• Engine Type: 494
• Wrist Pin: 18mm
• Note: Fits rotary valve, liquid-cooled motors only

Why Forged?

Wiseco is the only aftermarket piston manufacturer in the United States that produces pistons exclusively using the forging process. Starting with aerospace-grade aluminum, forging compresses the material's molecules, increases density, and aligns the grain flow of the alloy. The result is a piston with superior resistance to impact and fatigue, improved ultimate strength, and better ductility compared to cast alternatives — critical qualities in high-performance snowmobile engines where increased compression and horsepower place extreme demands on internal components.

USA Engineered and Manufactured:

Wiseco forges all pistons and produces all forge tooling in-house in the USA, allowing complete control over the manufacturing process from raw aluminum bar stock through finished skirt-coated parts. In-house dyno testing and finite element modeling (FEM) software ensure each piston design delivers maximum strength with minimum weight.

Important: Wiseco pistons must only be used with Wiseco rings. Ring types are not interchangeable between piston lines. Cylinder sleeves must be purchased separately.