Hi,
Here are the steps to replace those big fat stock rear turn signals. I used MoTrax long stalk arrow turn signals and spacers.

1. Remove old turn signals. I used a socket to remove the nut on the underside. Carefully pull out the signal. It will still be connected to the wire. I removed the screw from the amber lens to slide as much of the housing away from the wire. This enabled me to have a lot of wire to play with.

2. Remove the old grommet (Pull on one side and it will come out). Insert new spacers and put new turn signals in the hole. In order for the spacers to fit properly, you will need to place the spacers so it's like they are cupping between the plastic. It should look like this between the plastic: (( and NOT like this: ()

3.Splice the old and the new wires in order to make the connection. Make sure the connection is good. Connect the green wire from the bike to the black/white wire of the new signal. Then connect the black/white wire of the bike to the solid black wire of the new signal. It works best to test the lights after both sides have been connected.

*I stripped about 1 1/2 inch of wire to make sure the connection was long enough. I found out that if the wire is not long enough for the connection, it will blink fast and then not blink. *

4. Once you have tested the connection and it's correct. Put some electrical tape around the wires and push the excess up through the hole of the underside (which feeds under the seat).

And that's it. I hope it helps someone.
Some pictures are attached:
Deelight