Twin Power 4.250 Big Bore Cylinders For Harley FL High-quality big bore cylinders from Twin Power. OEM style black textured powdercoat finish with highlighted fins. Cast in iron liners for strength and durability and finish honed. Features: Includes cylinder head dowels Direct bolt-in, requires no machine work to crankcase or cylinder heads Increases 107 engines to 124 and 114 engines to 128 Piston kits and gasket kits sold separately Wrinkle black finish with highlighted fins Sold in pairs