I originally posted this on the Guzzitech forum, but now we have a forum of our own I thought I'd copy it here. It has been edited a little so it makes some kind of sense on this forum.
I have finally ran out of reasons not to buy a GPS. After Santa failed to deliver it was a case of "buy it yourself or go without." After reading up on bike GPS units on the net I went for the Garmin Zumo 550.
I'd read a post where a Norge owner had the idea of mounting the unit between the screen mounts.
I really liked this idea and discussed it with the guy at the GPS place. He was really helpful and we went out to the bike a few times with the Garmin and various bits of fitting hardware to work out a way to do it. In the end it turned out to be suprisingly easy, so heres how it went. It might be worth mentioning that my bike does not have the electrically adjustable screen, so I do not know if this would work on bikes that have that feature.
Aside from the mounting hardware that comes packaged with the Garmin I only needed to buy one extra piece, a RAM B-272 thing-a-me-jiggy
http://asp.ram-mount.com/rammount/productdetail.aspx?partnumber=RAM-B-272U
This picture shows the bracket mounted to the right screen mount. I used a 8mm x 35mm bolt with a nyloc nut to mount the RAM fitting through the upper adjustment slot in the screen mount. I also turned the adjusters so that the knobs are to the outside. The supplied double ended arm is then attached between the RAM fitting and the Base Plate.
After a bit of fiddling and adjusting I got it pretty much where I wanted it and tightened everything up. This is how it looks from the saddle with the GPS in place. I like that it is in line of sight and that it does not obstruct my view of the instrument panel at all.
A wide shot (for no particular reason)
As for the wiring I initially intended to and make use of the TomTom power cable that is hidden away on the bike. I found the lead by moving the fuel tank back a bit from the steering head but was not happy with the lack of length which would have made it a bit difficult to work on. I also noticed it had no power when the bike was off. I wanted to have power to the GPS even with the bike off. So I decided to use the supplied power cable with in-line fuse to hardwire directly to the battery. The cable is more than long enough for this. I ran the cable from the battery along the left frame tube to the steering head (you'll need to raise the fuel tank to do this), I used a few cable ties along the way to keep it all tidy. The power cable was then brought it up and around the right side of the instruments, and from there up to the Base Plate. If you look carefully some of the wiring is visable in the first picture. There may be ways to do this so that the wires are more concealed but this is very quick and easy and the wiring is not obtrusive.
So thats it. The really good part of this is that I did not have to make any modifications to the bike to fit the GPS. So when I remove the unit it will be like it was never there. I've found the position of the unit makes it very easy to see and use, no need to divert eyes too far off the road.
The Zumo is a great bit of gear, very intuitive to operate and quick to learn. Since the original install I've put a lockable knob on the mount as thieving scum will apparently steal GPS mounts, even without the actual GPS.
The only downside is that I now have no excuse for getting lost
