My Zumo tachometer
This may sound weird but....1)I have my zumo mounted to the dash behind the shield on my 08 990. I installed a reinforced piece of aluminum mounted to the headlight frame assembly when I had the bike apart. This brace definitelysecures the dash due to weight and vibration. 2) I used a Ram mount with rubber between the base of the mount and the dask.
The weird thing is that when i am tooling around in gear (NOT 1st GEAR) and my revs get to around 2800-3000 the vibration of the zumo mandates a downshift to the next lower gear and at 3000 rpm or higher, the unit has no vibration is as smooth as glass (kind of).
I assume others expereince a smoother ride at higher revs and by keeping the bike in the 4000-6000 range.