Thats a +2mm BigBore Kit and will turn your bike into 159cc !
Complete kit with gaskets, cylinder, piston, rings, pin and clips
Compression ratio: 11.7:1
When using Hot Rods crankshaft 4175 makes 166cc
-Ready-to-install, direct bolt-on cylinders require no re-plating and look virtually identical to the OEM cylinders
-Cylinder kits include matched Vertex pistons to ensure longevity, performance and reduced engine noise
-Nickel Silicon Carbide (Nikasil) plated for long life
-Honed to exact size for easy piston installation
-Big bore cylinders do not require machine work (unless noted)
-Made in the U.S.A.
-Replaces Honda OEM cylinder 12100-KSE-670, 12100-KSE-671, 12100-KSE-672