Personally, I wouldn't put any time or money into reviving that motor when a new motor kit is relatively inexpensive. But if you want the challenge, go for it. I am not sure what the black stuff is on the windings from the picture. It looks a bit glossy and may not be charring from overheating. Overheating can definitely damage the insulation on the windings and cause a short. There aren't many geared hub drive motors that are 1000W. Maybe the MAC or GMAC motors. The GMAC doesn't have a clutch and will have cogging like a direct drive motor. Grin has built a workaround to that into their CAv3 that applies a little bit of power to the motor while you are coasting. Grin's Ezee motor says that it rated 500-1000W. Or are you thinking about a Bafang BBSHD mid-drive? If so, you will need to replace your rear wheel as well as buy a motor kit.