Cylinder Works Big Bore Cylinder Kit +4mm 434cc 11.3:1 (41001-K01)

• Ready-to-install, direct bolt-on cylinders require no re-plating and look virtually identical to the OEM cylinders
• Big Bore Kit gives your vehicles more displacement
• Cylinder kits include matched Vertex pistons to ensure longevity, performance and reduced engine noise
• Nickel Silicon Carbide plated for long life
• Kits come complete with big bore gaskets, cylinder, bigger piston, rings, pin and clips
• Made in the U.S.A. and Italy

**NOTE: 2004-2009 CRF250R2004-2015 CRF250X 269cc kit requires case machining to make the Big Bore kit fit.

2002-2014 YAMAHA YZ85 103.5cc kit requires case cylinder machining to make the Big Bore kit fit.

2002-2014 YAMAHA YZ85 107.8cc kit requires case and cylinder machining to make the Big Bore kit fit.