ORIGINAL: wossname
So I should end up with this (see image).
My motor has a red dot next to one of its tags, I assume that's the positive one(?)
If the motor is not geared... yes the red dot gets the positive lead, and the picture s correct.... for the diode...
The setup you have will work... but you should have 3 capacitors. One from each wire to the morot case... and one between the wires, parallel to the diode. Sometimes the - pole of the motor is grounded to the "can" and inthat case... you may as well just have one capacitor from + to the can (or the - lead) because the one from - to can is useless. (and the other 2 would be in parallel)
Mine was in a geared drive setup and the red dot got the negative lead. (motor "neutrally timed" so running "backward" was not a problem.)