How I hooked my supply up

The first thing I did was plug this adaptor, "by itself into the bike".  I installed fresh batteries in the bicycle.  I used a digital multimeter to measure 6 volts across the pins.  I put my red "+" lead on the right pin and my "-" black lead on the left pin and I got a +6 volt on my multimeter.  If I got a -6 volt on my multimeter then I would have known that I was hooking my meter up backwards.  Now I know Right pin is Positive and Left pin is Negative.  I also did a Ohm, or continuity check, from the center pin to the Right pin.  I found that they were shorted.  That is what I expected and hoped for.

*Note: Take your alkaline batteries out of you bike when using a dc supply.  They might try to charge with a supply.

As you can see in this picture,  there is a "+" above the sideways word tip below.  This says tip is positive.

Once I found out how to hook the plug up I marked it.  I used a sharpie to mark the plug and the cord, see the "-" above the bottom mark.  This made my plug a no brainer so I could figure out how to hook it up in a few secs if I ever needed to figure it out again.