4-Stroke CDI Ignition Coil The 4-Stroke CDI Ignition Coil gives spark to the 49cc 4-stroke Flying Horse 5G and Huasheng 142F bicycle engine kits To install start by removing the magneto and pull start cover. Remove the spark plug cap from the spark plug, disconnect the kill switch wire from your kill switch, and remove the CDI. Bolt the new CDI above the magneto flywheel, install the spark plug cap back on to the spark plug, connect the kill switch wire to the kill switch, reinstall the cover, and you're ready to ride