premise: How can you mount a new sprocket on a bicycle and what tools do you use?
hypothesis: locate sprocket on axle hub, cut the rubber isolator to the center,  decompress the chain sprocket to the spokes, Leave the cover plate on the bicycle , then you must remove the narrow drive sprocket from the engine and install a wider tooth drive sprocket obtained from your dealer to match the 415 chain. Use spark-plug and wrench to turn engine crankshaft sprocket to feed chain around it, fit chain, reconnect the masterlink, adjust the chain, and install the chain guard.