...i.e. the little metal sleeve that goes in some rubber pieces to keep the fastener from crushing the rubber, like in the K model's rear turn signal mounts. I did this on Frankenbike last night, as I was sick of looking at squished rubber.
All you have to do is get a 12X6.8 ring terminal, and cut the crimp part to length. You may have to spread it a little depending on your fastener size. Also, don't forget to de-burr after cutting! The cutting went easy, as the ones I got were brass plated in white metal.
Checking the bolt fit
After the cut
In the rubber
Hope this helps
Gonzo