Wiseco K129 Forged Piston Kit Yamaha Standard Bore - RD350 RD400 64mm

The Wiseco K129 is a complete forged piston kit designed for the Yamaha RD350 and RD400 2-stroke engines at the standard 64.00mm bore size. Engineered and machined in the USA, this kit delivers the strength, precision, and reliability that Wiseco has built its reputation on across decades of motorsport competition.

Key Features:

• Forged High-Silicon Aluminum Construction: Each piston is forged from high-silicon, low-expansion aluminum alloy, providing superior tensile strength, reduced weight, improved heat transfer, and extended service life compared to cast alternatives.
• CNC Diamond-Turned Finish: Precision CNC machining ensures a consistent, exact finish with zero size variation, allowing confident installation in cast iron, chrome, Nikasil, and boron composite cylinder bore compositions.
• Dedicated 2-Stroke Forging: The piston profile and lightening operations are purpose-engineered for this specific 2-stroke engine application, optimizing the strength-to-weight ratio for performance and durability.
• Standard 64.00mm Bore: Designed for stock bore cylinders; oversize options are also available in the K1xx series for worn or resleeved cylinders.
• Complete Kit: Includes Wiseco forged piston(s), piston ring(s), wrist pin(s), and circlips — everything needed for a full top-end piston replacement.

The Wiseco K129 piston kit is an ideal choice for riders rebuilding or refreshing the top end of a Yamaha RD350 or RD400, delivering proven OEM-spec dimensions with the added confidence of Wiseco's forged quality.