Close up of the connections to the motor 1.

Grey is the negative lead, orange the positive. With wire this thin, I dont strip the wire with strippers. I melt the plastic at the desired point with the soldering iron, and gently pull the covering off betweeen thumb and finger nails to reveal the bared end. This reduces the risk of breaking the strands to a minimum but the ends look a bit untidy, as seen in this close-up.

Note that the brush cap with the spring is now at the top. This prevents the motor from contacting the chassis.