This page is a bit historical. In the old days, the PC-3 required a serial connection to your computer, and you'd have to have the bike ON in order to download a map to or from the powercommander. This is pretty inconvenient, since you can die from the exhaust fumes if you're working inside in the winter
The other reason to have one of these is that it is the only way to adjust your throttle position sensor setting on the Powercommander. If you didn't have this, you'd have to run the bike at 100% throttle in neutral gear with the engine ON. Mr Engine wouldn't like that very much, and your neighbors wouldn't like it all that much either.
The "power adapter" is just a way to supply power to the PC-3 without having to run the bike - so it gives you plenty of time to work on your map, download it your laptop computer, or upload a new map from the computer to the PC-3.
And you can leave the bike OFF while you crank the throttle to 100% to adjust the TPS settings. As long as the PC-3 is attached to the 9V battery you can do all this without running the bike, without dying from carbon monoxide, and without waking the neighbors.
In the old days, they would charge extra for the power adapter, which never made any sense. So this page was constructed to show you how to make your own power adapter so that you would not have to buy one.
If you're new to the GSXR and Powercommander©, then you won't need to do this : the present generation of PC-3 all use a USB connection to your computer, and all of them come with a "power up" adapter which is the same thing as my "power adapter". It will let you connect your PC-3 to your computer and program it without even attaching it to the bike. So this is a real improvement.
But in case you have the need, the diagram and photograph of the finished product are shown below.
Again, this adapter uses two serial connector plugs, which you can get for 50¢ at Radio Shack. I just used 9 short segments of wire to connect the 9 pins of the male adapter to the 9 receptors of the female adapter. Each different colored wire just makes those connections. Once I had it the way I wanted it, I used a hot glue gun to secure everything at both ends, and to insulate against any shorts.
The only important thing to know here is which pins have to get the +9V and GND connections. As you can see, the 9V battery connector should be connected by "side tap splice" into the wires for pin 1 and 5. This is shown in the diagram.
Leaving a short section of wires between the two serial connectors allows me to bend the whole apparatus to 90 degrees to make it easier to plug into my PC-3, which in my case is mounted in the trunk of the bike.
If you get one of these automatically with your PC-3 now, it's a good thing to have. Just flick the ignition key to ON (don't start the engine) and bingo -- you can set your power commander maps AND adjust your software throttle position sensor with the engine off. Very very cool. My TPS setting in the Powercommander© was only off by about 3%, but still, it's cool to know I can adjust it whenever I feel like it.