Wiseco Complete Bottom End Rebuild Kit-Yamaha-YZ 250F-03-11 Each kit contains crankshaft and connecting rod, all applicable bearings, and complete bottom end gasket kit made to meet or exceed OEM Wiseco connecting rods are double forged from a dedicated forging and feature shot peening, oil slots, and coated bronze thrust washers Bottom end gasket kits are made from premium materials, exceeding OEM standards, to provide exceptional seal between critical mating surfaces Main bearings are manufactured to the highest quality standards. Each is case hardened for maximum life and smooth operation at high RPMs Corrosion resistant surface treatment to prevent corrosion and pitting over long term use or storage. This will add to the life as well the strength of the assembl