Wiseco PK138 Pro-Lite Forged Piston Kit Bore for Yamaha - 2-Stroke 66.0mm RZ350

The Wiseco PK138 is a Pro-Lite forged 2-stroke piston kit designed with a 66.0mm bore (513M) for the Yamaha RZ350. As Wiseco's staple 2-stroke piston line, the Pro-Lite series delivers a proven combination of performance, durability, and value for both recreational riders and serious racers.

Key Features:

• Forged High-Silicon Aluminum Construction: All Wiseco Pro-Lite pistons are forged from high-silicon, low-expansion aluminum alloy, delivering superior strength, reduced weight, improved heat transfer, and extended service life compared to cast alternatives.
• Dedicated Forging Design: Application-specific forgings utilize aerospace-grade alloy with a dome geometry optimized for improved flame travel, and refined skirt profiles engineered for stability and smooth cylinder bore operation.
• CNC Diamond-Turned Finish: Each piston is diamond-turned on CNC computer-controlled lathes, ensuring a precise finish with no size variation and consistent installed clearance for maximum power, minimal wear, and an optimal seal at operating temperature.
• Universal Cylinder Compatibility: Compatible with cast iron, chrome, Nikasil, and boron composite cylinder bore compositions, making these pistons a versatile choice for both stock and rebuilt cylinders.
• Oversize Availability: The Pro-Lite line is available in a wide range of oversizes to extend the service life of worn cylinders. Chrome, Nikasil, and boron composite cylinders can be re-sleeved to accept Wiseco oversizes.
• Liquid-Cooled Application: Engineered specifically for the liquid-cooled Yamaha RZ350 two-stroke twin.

Kit Contents:

• Pro-Lite forged piston (per cylinder)
• 66.0mm ring set (2598CD)
• 16mm wrist pin (S486 — 16mm x 2.175", non-chromed)
• Round wire pin locks / circlips (CW16, pair)

Backed by over 70 years of motorsport engineering experience, Wiseco Pro-Lite pistons are trusted by both everyday enthusiasts and competitive racers across motocross, supercross, and road racing. The PK138 kit provides everything needed for a complete top-end piston replacement on the Yamaha RZ350.