The Cylinder Works Big Bore Cylinder Kit is a complete high-performance top-end solution for select Yamaha YZ250F and WR250F models. Designed with an 80.00 mm bore and a 13.5:1 compression ratio, this kit increases displacement by 3.0 mm over the standard bore while maintaining a stock-style appearance. Cylinder Works part number 21010-K01 is engineered for reliable fitment and consistent performance on compatible Yamaha engines.
Included components feature the cylinder, matched Vertex piston kit, and required gaskets for installation. The piston and cylinder are precision matched to support longevity, responsive power, and reduced engine noise. The nickel-silicon-carbide-plated cylinder provides a durable bore surface designed for extended service life, while the stock-like exterior helps preserve the original appearance of the motorcycle. No machine work is needed for installation when used with the specified compatible application and components.
This Cylinder Works kit fits 2014 through 2018 Yamaha YZ250F models and 2015 through 2019 Yamaha WR250F models, subject to the vehicle’s exact year and configuration. The included top-end gasket kit does not include valve stem seals. Replacement pistons, gaskets, and ring sets are available separately for future servicing. Verify engine specifications and model fitment before installation to ensure proper compatibility.
Features:
- Complete big bore cylinder kit with cylinder, piston kit, and gaskets
- 80.00 mm bore with a 3.0 mm increase over standard bore
- 13.5:1 compression ratio for enhanced engine performance
- Matched Vertex piston for durability, performance, and reduced engine noise
- Nickel-silicon-carbide-plated cylinder for extended service life
- Stock-style cylinder appearance
- No machine work needed for specified applications
- Top-end gasket kit does not include valve stem seals
- Fits 2014-2018 Yamaha YZ250F and 2015-2019 Yamaha WR250F models
- Cylinder Works part number 21010-K01
Fitment:
2014 Yamaha YZ250F
2015 Yamaha WR250F
2015 Yamaha YZ250F
2015 Yamaha YZ250FX
2016 Yamaha WR250F
2016 Yamaha YZ250F
2016 Yamaha YZ250FX
2017 Yamaha WR250F
2017 Yamaha YZ250F
2017 Yamaha YZ250FX
2018 Yamaha WR250F
2018 Yamaha YZ250F
2018 Yamaha YZ250FX
2019 Yamaha WR250F
2019 Yamaha YZ250FX