Flying Horse 66cc/80cc 2-Stroke Motorized Bicycle Upper Head Gasket &ndash; Gas Bike Cylinder Head Top Aluminum Gasket The 66/80cc Head Gasket (Top) is the direct replacement for the top head gasket for any 66/80cc bike engine kit To install, simply remove the top head cap from your motor and remove the top head gasket. Replace with the new top head gasket, torque the top head cap back down, and you're ready to run Compatible with engines that have 8mm head studs, including Flying Horse, Mega Motors, Grubee, Power King, and Stinger bike engine kit motors