Hot Rods Crankshaft Stroker Yamaha 4179Stroker CrankshaftFactory 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