RAM-B-149Z-GA26U: RAM Bike / Motorcycle Handlebar Mount for Garmin Nuvi 710, ...
The Ram Motorcycle Mount works really well.  I am impressed how well it holds the GPS and doesn't budge at all.  No vibration while going down the road.  It took me awhile to get it set up just right, but once I did it was perfect.  No instructions at all, but it is pretty straight forward on setting it up.  It just takes awhile to tighten everything down so it doesn't move.  About an hour from opening the product to getting it set up on your bike.