Yamaha Motor Co., Ltd. 5CU-11631-00-B0 Piston

Description:

The Yamaha 5CU-11631-00-B0 piston is used in two-stroke motorcycle engine systems. Commonly installed in Yamaha YZ250 (1999–2000 models) and similar high-performance motocross engines requiring standard bore piston replacement. Maintenance teams, engine rebuilders, and motorcycle technicians use this part for engine rebuild, compression restoration, and performance maintenance.

Applications:

The Yamaha 5CU-11631-00-B0 is used in motorcycle engine systems to convert combustion energy into mechanical motion by transferring force from the expanding gases to the connecting rod and crankshaft. It is widely applied in motocross bikes, racing engines, and two-stroke performance setups where precise piston fit, high durability, and optimal combustion efficiency are critical.

Technical Specifications:

• Compatible with Yamaha YZ250 (1999–2000 models)
• Product type: Standard piston (STD bore)
• Function: Converts combustion pressure into mechanical motion
• Bore size: Approx. 66.36 mm (standard configuration)
• Material: Aluminum alloy piston construction for heat dissipation
• System role: Core engine component in crankshaft and piston assembly
• Mounting: Connected to connecting rod via wrist pin
• Application: Two-stroke motocross and performance engines
• OEM part number: 5CU-11631-00-B0
• Condition: Genuine OEM part, often available as NOS or aftermarket equivalent

Common Replacements:

• Yamaha 5CU-11631-00-A0
• Yamaha 5MW-11631-00-B0
• Yamaha 5NX-11631-00-B0