Bore Stroke :81.0 mm (3.189 in) x 62.6 mm (2.465 in) , Compression Ratio: 11.5 : 1 , Engine :645 cc (39.4 cu. in), 4-stroke, liquid-cooled, DOHC, 90-degree V-twin , Fuel System :Fuel injection , Ignition: Electronic ignition (Transistorized) , Lubrication: Wet sump , Starter: Electric ,