Can your motor :
Mabuchi EM-400 Brushed DC Motor 7.2V 19200 RPM 3.26 oz-in
Product Code : RB-Gws-16
be substituted for for a Multiplex Permax speed 400 6 volts brushed motor…Thank you, Russack
Normally when you substitute a motor, it needs to have the same physical dimensions (overall size, shaft size/ diameter) as well as the specifications including voltage, RPM and torque.
Can you provide these specs for the motor you are trying to replace?