"With experience born on the raceways and roadways and a dedication to innovation, there's plenty of reasons to insist on the new Honda GX660 V-Twin engine. There's superior engine design, with a 90 configuration that reduces vibration and allows a compact footprint. There's superior construction, with a forged steel crankshaft and an integrated cylinder head. Fewer parts means better durability. There's a digital CDI ignition coil that ensures improved fuel economy and lowered emissions. There's even improved air cleaning, meaning that you can wait 5 times longer between filter changes. Honda gives their engines a 3-year limited warranty. Bolt Circle in. 7 3/4, Governor System Mechanical, EPA/CARB Approval California Air Resource Board Yes, Shaft Length in. 3.11, Compression Ratio 9.3 1, Start Type Electric, Torque ft./lbs. 35.2, Engine Type Air cooled, Bore x Stroke in. 3.1 x 2.8, Ignition System Digital CDI, Cylinders qty. 2, Shaft Rotation From PTO Shaft Side Counterclockwise, Carburetor 2-barrel, fuel cut solenoid, inner vent, Air Cleaner Type Dual element, Oil Capacity qt. 2.3, Shaft Diameter in. 1, Lubrication System Full pressure, Engine Displacement cc 688. Full pressure lubrication system Forged steel connecting rod Mechanical governor system 50-state compliant engine"