Wiseco Complete Bottom End Kit Yamaha Yz250F The Wiseco Complete Crankshaft Kit offers superior durability and performance for motorcycle engines. Precision-engineered to meet OEM specifications, this crankshaft assembly guarantees reliable functionality even under strenuous conditions. Features: Crankshafts are factory assembled and precision trued to OEM specifications Double-forged Wiseco connecting rods maintain superior dimensional consistency through improved grain flow Shot-peening eliminates residual stresses and smoothly blends the rod forging surfaces Corrosion-resistant surface treatment Crank pin bearing radial running clearance is optimized to ensure maximum performance Precision honing ensures ultra round bearing surface Precision engineered oiling slots maximize rod strength and bearing life Double-drilled small ends provide the piston pin with extra lubrication and cooling, reducing distortion of top end due to thermal transfer from the piston Kit includes crankshaft assembly, main bearings, and bottom-end gasket kit Note: Images are for reference only.