CRANKSHAFT BOTTOM KIT 2003-2013 YAMAHA YZF250 WISECO WPC140

A factory-assembled crankshaft kit supplied with main bearings and a gasket set for complete bottom-end service. Precision-trued to OEM specifications, it incorporates advanced surface treatments, lubrication features and tightly controlled clearances to support durability and performance under high-RPM operation. The crankshaft kit includes a crankshaft assembly, main bearings, and a gasket set. Features include connecting rods that are double-forged to maintain superior dimensional consistency through improved grain flow, shot-peened to eliminate residual stresses and smoothly blend rod forging surfaces, and have a corrosion-resistant surface treatment. Top and bottom end rod bores are case-hardened to 58–62 RC to optimise bearing running surface. Crank pin bearing radial running clearance is optimised to ensure maximum performance, and precision honing ensures an ultra-round bearing surface. Precision-engineered oiling slots maximise rod strength and bearing life. Double-drilled small ends provide the piston pin with extra lubrication and cooling, reducing distortion of the top end due to thermal transfer from the piston. Silver-coated bronze phosphor thrust washers with a dimpled design increase oil retention and reduce friction between the rod and washer interface. Crank pin bearings are manufactured with the highest-quality hot-rolled steel and case-hardened to 58–62 RC. Manufacturer: Wiseco.