I made my own mount extender (the same thing that TT charge a small fortune for) and fitted it to the GPS mount bar. I'm fairly sure there is another thread about this already, but here goes.
I did have it on the handlebars, using the RAM mount and it was fine, no problems. I just didn't like it out of my field of vision so I moved it to thr GPS bar. I'm not sure what Yamaha were thinking but the GPS bar is useless, because of the screen you cannot actually get a GPS mounted on it! So into the workshop.
At first the movement on the GPS was awfull, it vibrated so much that it was pretty unreadable at high revs, so I purchased the TT antivibration mount and it's fine now. Although at low revs (tickover) the whole subframe (lights, clocks, screen etc) vibrates - I think the subframe mountings need a bit more strenghth to them - it is only a couple of lenghts of 10-15mm steel!
Power is provided from an auxilary circuit as I have 12v power take off, heated grips, and ther'll be some driving lamps when I get the change to fabricate a bracket.....