Wiseco 4985M10000 495cc Big Bore ATV Piston Kit 100mm 11.7:1 Compression

The Wiseco 4985M10000 is a high-performance forged piston kit designed as a big bore upgrade, delivering a 495cc displacement with a 100.00mm bore diameter at 11.7:1 compression ratio. This kit represents a 4.50mm oversize over stock bore and features a dished piston crown optimized for the 4-valve combustion chamber design.

Key Features:

• Forged high-silicon, low-expansion aluminum alloy construction for superior strength, reduced weight, and improved heat transfer
• 100.00mm bore diameter — 4.50mm oversize for big bore applications
• 11.7:1 compression ratio with dished piston crown for 4-valve engine compatibility
• 495cc displacement big bore configuration for increased power output
• Innovative forging design and optimized piston skirt profile for maximum horsepower and torque
• Complete kit includes piston, rings, wrist pin, and circlips

Important Installation Notes:

• This oversize piston requires cylinder boring or sleeving to the specified 100.00mm diameter
• Compatible with cast iron, chrome, Nikasil, and boron composite cylinder bore compositions
• Cylinder resleeving is required for chrome, Nikasil, and boron composite cylinders

Wiseco has been the leading U.S. manufacturer of forged powersports pistons for over 75 years, supplying both competitive racers and performance enthusiasts with precision-machined components built to withstand the most demanding conditions.