Flying Horse 66cc/80cc 2-Stroke Motorized Bicycle Engine Crank Connecting Bearing &ndash; Gas Bike Piston Pin Bearing Replacement The Crank Connector Bearing helps the piston ride smoothly on the crank arm of most 48cc and 66/80cc 2-stroke bike engine kits To install, begin by uninstalling the cylinder and piston. Once the crank arm is exposed, remove and replace the existing connector bearing. Assemble the piston around the bearing, then the cylinder and cap back on the engine- then you're ready to ride Note: Some 2-stroke cranks have bushings instead of bearings. If you have bushings within your crank you cannot install a connector bearing without first replacing the crank arm