4173 Stroker Crankshaft Yamaha YFZ450 2012 2013

Features: Factory assembled and trued to OEM specifications. Drop in replacement crankshaft requires no modification unless noted . CNC machined and dynamically balanced to suit the increased stroke. Add +2.00 mm to +4.00 mm of stroke depending on application. Uses stock piston unless noted. Main bearings not included . Can be matched with Cylinder Works Big Bore cylinders to get significant displacement and horsepower gains. Not re-buildable as the rods are shorter than OEM.. Connecting rod side clearance is 0.20 mm - 0.55 mm. When using Cylinder Works # 21001-K01 makes 500 cc. Final displacement determined by application. Uses stock piston. Does not fit fuel injected R or X models..