I used an Acerbis mirror
for several months- they are for show only. They are useless for seeing what's behind you. I put a Ken Sean
folding dual-sport mirror on my bike. It works as well as any stock motorcycle mirror. You do need to replace part of the clutch perch for it. MSR
makes a mirror adapter that works great. The total price for both pieces (mirror and adapter) is about $35 US. I got the mirror from Dennis Kirk. The address to Dennis Kirk is http://www.denniskirk.com.
Search for part no 391305 in the dirt bike catalog.
Check out this link to the adapter from MSR
(scroll down on the page to see it): http://www.msracing.com/hpdual.htm
[This message has been edited by Rich in Orlando (edited 03-09-2001).]