Flying Horse 66cc/80cc 2-Stroke Motorized Bicycle Engine Piston Replacement &ndash; Gas Bike Piston (Piston #4) The 66/80cc Piston #4 fits most 66/80cc Flying Horse, Mega Motors, and RAW 2-stroke bicycle engine kits Height: 50mm; Width: 47mm; Skirt Width: 23mm; Skirt Height: 10mm; Piston Pin Port: 10mm; Height from Skirt to Piston Pin: 5mm To install, all you need is a set of piston rings and piston clips. Use the stock piston pin and crank connector bearing to connect the new piston to your crank As there are many different pistons for each model of engine, please read the measurements of our pistons and reference your existing piston to ensure a proper fit.