Hello Ty,

    Those are heat disks. If you look close at the center, there is a solder
section that will melt out at a certain temperature. That temp should be
stamped on the disk. In other words, if the plug melts out, you have
overheated the engine, for what ever reason.
    So do not remove them, or let the engine over heat!

Howard
> I have a question for the list, I just received a
> longblock from AVP and it has these discs on each head
> about the size of a dime (one also on the case) and
> says "warrantee void if removed" the center is gray
> and
> is glued on does anyone know what the heck these are
> thanks Ty
> 90 westy with head leaking
>