Another thing you might be able to take a block of wood and tap on gear in reverse rotation. Meaning if your on the right side of the bike looking at crank, you would tap the primary gear counter clockwise, dont get to horseee with it though. That if you dont have a puller. A puller would be best. When you get it off, emery cloth the crank shaft a little. And I would install a new Key, probably dont cost that much, maybe 3.00, I would put a new key in it.