Hi,   
As the new owner of a, somewhat neglected, 83 Venture I have been doing some fluid changes, cleaning etc.   
Well, I decided to take apart the left hand control to clean it as it was kinda "sticky".   
I got a little ahead of myself and took out the internal screws (before snapping a couple of pictures) and then proceeded to have a handful of parts.    
I've put it back together but I seem to have a spare piece. I have, historically, found that usually there aren't any spare parts.   
I have added some pictures.   
Can anyone tell me where this bit goes?