If you want to use a GPS receiver on your naked motorbike you're in troubles. Now, that I bought myself a Garmin® GPS12 Map I wanted to use it for navigation while biking too.
My first attempt to mount the GPS receiver on top of the tank worked quite well. It showed in principle that the antenna wasn't shielded and the display was within sight while driving.
The cradle is built from:
The cradle is fixed to the bike with rubber bands. It doesn't score for beauty though.
All the commercial cradles I found attach to the 12mm enforcement you won't find on a naked bike's handlebar. In addition, the cradles have an offroadish look as well. There isn't even enough space for the cradle to mount without hiding the odometer. Finally, I decided to go for the Touratech® cradle.
It is designed for offroad usage and needs the 12mm bar found on every offroad bike's handlebar to be mounted. The solid rack is protected against vibration through rubber bits between the main cradle and the mounting plate.
My approach was to keep the main cradle but to replace the mounting plate. I fixed a block of aluminium alloy to the base of the mounting plate. The other end of this block is screwed to a pair of plates fitted into a flexible pad (sounds awful by now :-)
To achieve a more appropriate look the whole cradle was anodised in black.
The pad contains four extremely strong magnets (from hard-disk drives) to provide hold on the metal surface of the tank. Apologies to the poor saddler who nearly ruined his machines when sewing the pad. In addition there are four buckles to fix the cradle with straps (in case you want to mount it to an offroad bike with a plastic tank).
The power cable is connected to the bike via a small plug to be easily disconnected. This is a must for filling in fuel.
I put the cradle to test on a few local rides and for four weeks during my trip to Corse in May 2000. The GPS receiver doesn't replace a paper map, it's a valuable add-on though. Especially when riding through the Po plains in Italy by night or heavy overcast sky it was very helpful to have a map with an arrow telling me my position in front of me. The backlight display came in handy in these cases too.