If your teeth are gone on the big regulator gear sector, I actually managed to weld it up and file new teeth...see last post in this thread
http://www.peachparts.com/shopforum/showthread.php?t=135151
I'm not too cheap to buy a used regulator, but for all the hassle of putting the old one back until the replacement arrives, then repeating the exercise all over, it was easier to fix it (of course, having a mig helps). If the gear on the motor is gone, you're probably looking at a replacement motor.