Check out that very cool technical button up there in the right corner -
I'll save you the very easy search this time. Lots of good stuff there, worth spending 30 minutes reading it.
"Ensure each mirror is attached firmly at its three connection points and the gap between the mirror and the bike is consistent (about 1/8"). If a connection point seems loose or the gap is inconsistent, consider shimming the connection balls the mirror attaches to. To remove a mirror, smack the outside front of the mirror unit, towards the back of the bike, with the palm of your hand, being careful not to drop the mirror when it comes off.
The factory may have taped spare washers on the body side of the mirror (these may be bent "lock" washers). It's quite common for mirrors to come off when you hit potholes, bumps, other things, etc. A replacement mirror costs about $200 and you don't want to have one destroyed, especially if you're far from home. We recommend you firmly connect each mirror to the bike so if (when) it falls off it will stay with the bike.
Many riders use heavy duty wire tie wraps to secure the mirrors but some have reported that the sudden impact of a flying mirror can snap the ties. Some owners use twisted wire that but that could snap if pulled too hard, depending on the strength of the wire. Heavy fishing line may work if sufficiently strong (e.g., 100lb. vinyl coated stainless leader line and crimp sleeves).
If you want the very best option, Bob's BMW sells 1/16" aircraft-cable connectors made for this very purpose; they are about $18 a pair and they are very strong. (Call the number listed here)"
