Bob,
According to thesuperkids.com , the bmc 2000 watt motor has a dia. of 7.125" , and a 7/8" shaft , while the 1500 watt has a dia. of 5.75" , and a 11/16"-or 17mm. shaft , while the 1000 watt is approx. 5" in dia. , with a 1/2"or 12mm. shaft.
As for the rpm/v , I think I'll be running it at 36 volts for 4000 rpm , I'm not really sure about the gearing . I plan on buying an 11 tooth motor sprocket , and a 55t , a 66t , and a 77t wheel sprocket . just to do some testing with . Not real sure if it has enough power to pull the 5:1 . Was hoping that someone out there has one of these that might be able to give me some feedback .
Thanks though , hope that info might help you find out which one you have . The shaft on the 1500 and the 2000 are both 2.25" in length.
Torqueon,
Try the superkids.com . They have a kit for both with a programable Crystalyte controller . Or the motor by it's self. Go to the scooter parts then electric motors. hope this was helpful .
Thomas