Flying Horse 48cc 2-Stroke Motorized Bicycle Upper Head Gasket &ndash; Gas Bike Cylinder Head Top Aluminum Gasket The 48/49/50cc Head Gasket is a direct replacement for 48cc, 49cc, and 50cc 2-stroke bike engine kits 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 6mm head studs, including Flying Horse, Mega Motors, Grubee, Power King, and Stinger bike engine kit motors