BMW made an abbreviated mount for the top triple-clamp. Â
It holds the two instruments, the ignition switch and the dash panel.
I have one for sale for $25. Â It has never been installed on a bike. Â It does
not have any of the special rubber and steel washers and steel spacers, though. Â
If you are interested, I hope you didn't toss it too far! Â

I checked - those mounting bits ARE available from a dealer for not-too-much money.
Here are pictures: Â http://www.pbase.com/tomfarr/instrument_mount
#12 in the diagram:
