Flying Horse 2-Stroke Motorized Bicycle Engine Pintle &ndash; Gas Bike Pintle Repalcement The Pintle installs in the ferrule of the crank assembly for 2-stroke bicycle engine kits across the board: 48cc, 60cc, and 66/80cc's Installation will take advanced skills: you will need to first open the crank case to expose the crank. Near the end that the 10 tooth drive sprockets are on there will be a ferrule with a pin in it. Remove this pin and replace with the pintle, assuring your crank is aligned in the case properly. Assemble the case back together and you're ready to ride