I bought a set of class retro mirrors and some bar ends to mount them on. My roommate and I tried to decipher the instructions they came with to get the right combo of parts for the bar end. The problem is, we can't seem to get it tight enough so that it won't turn. The bar ends and the mirrors came with different parts. We used the bigger of the two metal spreading pieces that came with the mirrors. We thought we had it tight enough that it would be ok, but as I was riding the mirrors started to rotate forward.   

Any advise on what we may have screwed up, or which are the correct parts to use would be appreciated. 

Just did a little more searching on here and found this: http://www.ducatimonsterforum.org/index.php?topic=48977.0

He used the same pieces I did, so we must just not have had it tight enough. My roommate was afraid we were going to break the bolt.

Should I use a little blue lock tight on the bar ends?

you can tighten them down pretty well, but don't try to get it to the point they wont move at all.  Weather it is the bar ends rotating in the bar, or the mirrors rotating around your bar ends, if you give them a sharp tap, your mirrors are going to move.  That is how mine are, they don't move during normal operation, which is fine.

I think I used loktite on the screws that hold the mirror stalks to the bar end, but thats all.  The bar end fitted well and nothing moves on mine, even if I knock it (gently).

Thanks for the replies.

On mine you could turn the bar end with the mirror mounted to it, but I thought they were tight enough. going down the road the bar ends started to rotate from the weight of the mirrors. Buffalo has some of the worst paved roads I've ever seen, so that may have been a factor.