I recently purchased a Garmin C580 (Color Bigger Screen) to replace the Garmin GPS V (Small Screen...Waterproof) on my bike. Thanks to Headshrink, I modified the "Erector Ram" setup he used. Since I already had RAM pieces with the GPS V, I only had to purchase the C580 adapter (Mini Ball Mount), the RAM dumbell, the RAM 9mm mount. and a 1 3/4" RAM arm. I reused my 3 1/2" RAM arm and RAM Compact Base / Cradle Ball Adapter.
I had to use my phone camera for the following pictures, since my wife (Realtor) is working and has her camera with her. Maybe I can use her camera later and replace these with better pics.
You will also notice I still have the ball mount on the left clipon. This was used for the GPS V. Since the C580 is NOT waterproof, I have it under the ZG Sport Touring windshield and will enclose it with a ziplock bag as needed.
The blue arrows in the second picture show how I routed the power cable from the battery.