Brand New Part # KB542LCA.STD KB Performance 120″ Big Bore Super-Duty Forged Piston Kit for 117″ M8 Engines Fits Harley 2017+ M-Eight 117″ Models 4.125″ Bore Super Duty Series includes: Anondized top ring groove and crown New skirt coating technology is applied to the entire thickness of the piston-to-wall clearance for a zero install clearance; coating then abrades in on start-up to hone for the perfect fit per cylinder Skity coating eliminates piston rock for the best possible ring seal with no piston slap noise Round wire locks Steel nitride top ring with a Ductile Napier second Forced wrist pin oiling Flat Top 1.2cc design with oversized valve pockets to accept 1mm larger valves Compression Height 1.083″ Factory 117″ Cylinders can safely be bored to 4.125″ through 4.165″ Bore Size: 104,77 mm / 104.77 mm Piston Size: Standard Displacement: 117″ Stroke Length: 4-1/2″ / 4-1/2″ Compression Ratio: 11,0:1 / 11.0:1