[url=http://www.ebay.com/gds/Electric-Scooters-Repair-/10000000005722249/g.html said:
Electric Scooters Repair by rw2000w[/url]"]
Testing a brushed DC motor. (Typically marked MY1018, MY1020, etc. available on EBAY)
Mount the scooter in a safe sturdy position so that if/when the motor turns, nothing will be in contact with it or its chain, wheel or other moving parts. Then unplug or otherwise remove all connections to the motor, leaving just the two leads that enter the body of the motor, usually red and black. Connect a 12 volt battery carefully as follows. Red connects to the battery's positive terminal, black to the negative terminal. There will be a spark as the final connection is made, and the motor will instantly spin, so I connect the positive lead to the battery terminal firmly and then just brush the negative lead from the motor against the other battery terminal. I do this, because a dead short in the motor would burn up the wire leads if tightly connected, and damage or heat the battery. If the motor is good, it will spin, so again, make sure it is mounted in such a way that it will not harm anything. If the motor is rated for 36 volts, and you connect a 12 volt battery, it will go slower than its maximum speed. If it is rated for 12 volts, it will go at its maximum speed. If you connect the wires backwards, many scooter brushed motors will go in reverse.