Which bike?

Anyone tell me which bike this is from?

http://www.neji-nakamura.co.jp/photo/bolt/bolt.jpg

 

It's not. It holds my vice onto my bench. Wondered where it had
gone.

 

flash says...

Looks like a front disc bolt from a 1981 RD250LC (no number on head,
zinc plated and shouldered like a disc bolt should be), but I could be
wrong.

 

Could be any. Looks like a hero blob for pikeys.

 

I can, but I'm a self employed contractor,

Send me £50 and I will identify the bolt to an accuracy coefficient of
37%...

Dave

 

"It's a metal one"

 

<G> You're probably right, knowing you.