Athena P400485100030 Big Bore Cylinder Kit (144cc) - 4.00mm Oversize to 58.00mm, 14:1 Compression

Bore: 58.00mm
Sizing: Sizing Not Available

Race cylinder kits include a nickel carbide coated cylinder ported to Factory.
Works specs, special hard anodized exhaust valves, complete piston kit and a top end gasket set.
Factory cylinder kits include all parts in the Race kits plus an aluminum cylinder head with removable brass dome allowing for higher compression and antidetonating features.
REAR WHEEL HORSE POWER: 37.6 HP / 11.200 RPM.

Kits include aluminum cylinder with nickel-carbide coating designed with larger water jackets. Includes Forged piston, rings, clips and pin. Athena top-end gasket set includes required seals and hardware. Easy-to-follow step-by-step installation instructions. Most are bolt-on; no machining required except where noted.

Vehicle Fitment:

2005-2021 Yamaha YZ125
2020-2022 Yamaha YZ125X