Description
The Yamaha YZ490’s original piston wasn’t built for sustained high-RPM performance or aggressive riding conditions. The Wiseco 478M08800 replaces worn or damaged pistons with precision-engineered internals that restore compression, improve throttle response, and extend engine life. If you’re rebuilding after a top-end failure or upgrading a tired engine, this kit delivers the reliability and performance you need to ride with confidence.
Wiseco has engineered this kit specifically for the YZ490 platform, ensuring proper bore diameter, pin fit, and ring gaps without modification. The high-silicon aluminum alloy resists thermal stress during extended use, while CNC-machined tolerances maintain the tight clearances that distinguish quality rebuilds from amateur work.
- Fits: Yamaha YZ490 (1982-1983)
- Material: High-silicon aluminum alloy
- CNC-machined for precision tolerances
- Includes piston rings
- Includes wrist pin
- Includes circlips
- Bolt-on installation
- Stock bore diameter
- MPN: 478M08800
