Wiseco Pistons PK1818 Top End Piston Kit Yamaha - 87.5mm YZ490 WR500

The Wiseco PK1818 is a complete top end piston kit designed for 1984–1993 Yamaha YZ490 and WR500 two-stroke engines. This kit delivers everything needed to successfully overbore or rebuild your top end to 87.5mm (546M) bore size, restoring power and reliability to your engine.

Wiseco pistons are forged from high-strength aluminum alloy, offering superior strength and heat resistance compared to cast pistons. The forging process produces a denser, tighter-grained material that withstands the extreme pressures and temperatures of high-performance two-stroke engines.

Kit Includes:

• Forged Wiseco piston (87.5mm / 546M bore)
• Piston rings
• Wrist pin
• Circlips
• Top end gasket set

Key Features:

• Forged aluminum construction for maximum strength and durability
• Precision-machined to OEM tolerances for proper fitment
• All-inclusive kit simplifies the rebuild process
• Engineered specifically for 1984–1993 Yamaha YZ490 and WR500 applications
• Oversize 87.5mm bore accommodates worn or damaged cylinder bores

Whether you are refreshing a worn engine or building a high-performance two-stroke, the Wiseco PK1818 provides the quality components necessary to get back on the track or trail with confidence.