Hello All,
Regarding the left hand thread mirrors found on some bikes (IE Royal Enfield, Buell, some Yamahas, etc.) If you have a set of normal mirrors (IE right hand thread) that you want to install. Just run a right hand thread tap through the hole and it will work just fine. Yes, I'll admit it sounds a little shade tree mechanic, but its not like its a motor mount or something critical.
GB