Cylinder Works Big Bore Cylinder Kit 72.00 mm for Yamaha YZ250, Part 21009-K01
Cylinder Works Big Bore Cylinder Kit 72.00 mm for Yamaha YZ250, Part 21009-K01
Cylinder Works Big Bore Cylinder Kit 72.00 mm for Yamaha YZ250, Part 21009-K01
Cylinder Works Big Bore Cylinder Kit 72.00 mm for Yamaha YZ250, Part 21009-K01
Cylinder Works Big Bore Cylinder Kit 72.00 mm for Yamaha YZ250, Part 21009-K01
Cylinder Works Big Bore Cylinder Kit 72.00 mm for Yamaha YZ250, Part 21009-K01
Cylinder Works Big Bore Cylinder Kit 72.00 mm for Yamaha YZ250, Part 21009-K01
Cylinder Works Big Bore Cylinder Kit 72.00 mm for Yamaha YZ250, Part 21009-K01
Cylinder Works Big Bore Cylinder Kit 72.00 mm for Yamaha YZ250, Part 21009-K01
Cylinder Works Big Bore Cylinder Kit 72.00 mm for Yamaha YZ250, Part 21009-K01
Cylinder Works Big Bore Cylinder Kit 72.00 mm for Yamaha YZ250, Part 21009-K01
Cylinder Works Big Bore Cylinder Kit 72.00 mm for Yamaha YZ250, Part 21009-K01

Cylinder Works Big Bore Cylinder Kit 72.00 mm for Yamaha YZ250, Part 21009-K01

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  • $1,255.75
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The Cylinder Works Big Bore Cylinder Kit is designed for Yamaha YZ250 two-stroke engines from 1999 through 2008. This complete kit includes a cylinder, matched piston kit, and required gaskets for a reliable top-end replacement and performance upgrade. With a 72.00 mm bore, the kit provides increased displacement over the standard configuration while maintaining a stock-style appearance.

The cylinder is nickel silicon carbide plated to support extended service life, improved durability, and consistent performance. Cylinder Works matches the cylinder with a Vertex piston to help promote longevity, reduce engine noise, and ensure dependable operation. The kit is designed for applications where no additional machine work is needed, helping simplify installation and reduce preparation time.

Fitment: Fits 1999–2008 Yamaha YZ250 models. This kit includes the cylinder, piston assembly, and gaskets. The top-end gasket kit does not include valve stem seals. Replacement pistons, gaskets, ring sets, and standard-bore replacement cylinders are available separately when service parts are needed. Verify engine year and application before installation to ensure proper fitment.

Features:

  • Complete big bore kit for increased engine displacement
  • 72.00 mm bore size for compatible Yamaha YZ250 applications
  • Includes cylinder, piston kit, and gaskets
  • Matched with a Vertex piston for durability, performance, and reduced engine noise
  • Nickel silicon carbide plated cylinder for extended service life
  • Stock-style cylinder appearance
  • Designed to require no additional machine work
  • Replacement pistons, gaskets, ring sets, and standard-bore cylinders available
  • Fits 1999–2008 Yamaha YZ250 models
  • Brand: Cylinder Works
  • Manufacturer part number: 21009-K01
  • Vendor part number: 422-21009K

Fitment:
1999 Yamaha YZ250
2000 Yamaha YZ250
2001 Yamaha YZ250
2002 Yamaha YZ250
2003 Yamaha YZ250
2004 Yamaha YZ250
2005 Yamaha YZ250
2006 Yamaha YZ250
2007 Yamaha YZ250
2008 Yamaha YZ250
2009 Yamaha YZ250
2010 Yamaha YZ250
2011 Yamaha YZ250
2012 Yamaha YZ250
2013 Yamaha YZ250
2014 Yamaha YZ250
2015 Yamaha YZ250
2016 Yamaha YZ250
2017 Yamaha YZ250
2018 Yamaha YZ250
2019 Yamaha YZ250
2020 Yamaha YZ250
2021 Yamaha YZ250
2022 Yamaha YZ250
2023 Yamaha YZ250
2024 Yamaha YZ250
2025 Yamaha YZ250