jremington:
You need to provide information about the power supply and the motor voltage and current requirements. A circuit diagram would help. The L293 needs protective diodes and is limited in the amount of motor current that it can handle.
The motors are FF-050 from CD-ROM, very stable and quiet motors, not even capacitors are needed with these ones. At stall, they draw less than 400mA, and the L293B is capable of handling 1 amp per motor.