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.

Features

• Precision-trued to OEM specifications and factory assembled


• Connecting rods are double-forged to maintain superior dimensional consistency through improved grain flow


• Shot-peened to eliminate residual stresses and smoothly blend rod forging surfaces


• Corrosion-resistant surface treatment


• Top and bottom end rod bores case-hardened to 58–62 RC to optimise bearing running surface


• Crank pin bearing radial running clearance optimised to ensure maximum performance


• 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 dimpled design increase oil retention and reduce friction between rod and washer interface


• Crank pin bearings manufactured with the highest-quality hot-rolled steel — case-hardened to 58–62 RC

Specifications

• Manufacturer: Wiseco


• Product type: Crankshaft kit with bearings and gaskets


• Included components: Crankshaft assembly, main bearings, gasket set

Cross-Reference OEM Part Numbers

• WPC140


• 56-229.WI

Vehicle Fitments

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  Yamaha YZ250F (2003–2013)