Each 2005 Kymco Filly is powered by a four-stroke, air-cooled, single-cylinder engine, which has two intake valves on the cylinder and generates 2.6 pound-feet of torque at 6,000 revolutions per minute. It has a bore and stroke of 39 x 41.4 millimeters (1.54 x 1.63 inches) and a compression ratio of 10.5 to 1. A carburetor fuels the engine, which can be ignited using the scooter’s electric starter or kick starter. Paired with the 2005 Filly engine is a Continuously Variable Transmission, which chooses from an infinite number of gear ratios for enhanced operation of the engine and consequent increase of fuel economy. Each 2005 Filly has a gas tank with a peak capacity of 1.6 gallons (6.1 liters).