Beware fellow CX500 and other bike owners.
You will often see for sale, brand new mirrors described as 'genuine replacement for original mirrors' The quality is not in question, as it is in keeping with 'pattern parts' However, please be advised that these replacement mirrors are actually NOT LONG ENOUGH.
I was unfortunate enough to purchase a set of these mirrors for my CX and fiited them on arrival; this was mid winter. Much later, in the spring, I happily rolled out the bike for its first run of the year, complete with gleaming new mirrors. Within minutes I realised that the only thing I could see in my mirrors, was me. I am a small guy but no amount of adjustment could set the mirrors in a position where I could see around my own body.
The mirrors I bought are still being sold on ebay and have the following number stamped on them 'Le9*4253' and JAC WIN. They are approximately 150 mm reach from the vertical spigot to the mirror mounting point. Be aware that for the CX, the reach has to be at least 200 mm to allow you to see the road behind you.
The only reason I did not return these mirrors was because of the elapsed time between receipt and using (four months). I have informed ebay (who have not acted), and the seller (who continues to sell them).
I have written this guide on safety grounds. My first ride was enough to prove that these mirrors are unusable and I quickly took them off.