Stray Set Screw

Maybe its from the T/S plugging period.
It looks to be around the size of the long oil return passage.

 

save it you can start to build a new bitsa bike from unused and unidentified parts...

 

Any other projects on the lift? Or maybe boxes of fasteners?

 

If you pull something apart often enough sooner or later you will have two of them

 

Its not a grub screw from a cresent spanner possibly? Adjustable spanner ?

 

Underside of a MKIII rear brake master cylinder?

 

After what you've been through, I can understand your paranoia about something being left out, but I think it came from something else.

 

I thought it was from one of my tools we had out but it’s too big.

 

I don’t allow those MkIIIs in my garage.

 

Is the paranoia starting to show?

 

I put a 70 set of cases together recently, I also did the AMR oil pump mod and also their recommended change to the timing cover oiling to match the later MK3 cover, the grub screw for that was 1/4 20TPI which looks like the one you have. There was no other grub screw any thing like it anywhere else on the assembly.

 

Where did the screw go exactly?

 

Into the timing side crankcase, on the outside into the hole that normally leaks oil when you take the timing cover off.

 

Oh, yeah, this engine would have never had that. It was sporting the original timing cover when I got it.

 

We now know the perfect revenge to perpetrate against a Norton owner. Sneak into the shop and leave an unidentified bolt on the bench. How well do you trust your wife? Murder by grub screw?

 

One of the, recently departed, tricks of Les Williams was to leave a gudgeon pin circlip lying around someone elses engine assembly area.

 

Dave, didn't you buy an assortment of plugs to seal the timing chest ? Could it be one of them? It looks to me like it's never had a key in it or been threaded into anything.


Cheers,

cliffa.

 

Can you confirm this is not something related to the tools you are using?

 

So far it doesn't look like that.

 

For some reason, when I saw this pic I thought of you @swooshdave