What is that thingy
 

There is a plate with a threded lug welded to the underside of my frame just behind the left pilion foot peg bracket.
Can anybody tell me what its for?
1996ss

Sounds like the place where the helmet lock should be.

Has any body els got one on there bike

Yes, I have to go with keefy boy it's the helmet lock bracket, only used on SLs cos' on the two seaters you those bits of bent wire under the seat instead :frog:

Sounds about right

I've got one on my 95 SL but I've also got a helmet lock up front by the tank.

I havent it must be an sl thing