Put it all back together today and it started as soon as the fuel lines and rail were full. Reset the bypass screws using my mercury columns and it's now running as sweet as a nut.
 But still not convinced I've solved the problem of why it didn't start on Monday.

Anyway, just for info, sensible position for clamp screw.
   

And silly position for clamp screw, (courtesy of BMW)

a timely find paul

I wonder if you did internal fuel parts ?

we have seen rubber break inside the tank before .

keep at it ol mate !

Thats one thing I don't like is not finding the reason and have it go away, I'm always waiting for it to happen again.

I agree totally...did the problem get solved or is it out to lunch for a bit or until I am a long way from home and it pissing down....just makes you feel alive the uncertainty of it all!!!

Yes, I'd much rather (sort of!) it stopped completely and be able to find the reason.

However, noting the weird happenings with starter motor brushes, I pulled the starter motor today and fitted my spare which I know has long brushes.
Dismantling the original which hasn't been disturbed for 28 years, showed that the earth brush was well worn, down to below 5mm long.
So, was this the cause? hoonose (apologies Rick)

Also fitted some 'orange top' coils while in that area, so that's another change.

Time will tell.

Paul.

Charlie, I haven't done the internal fuel lines as yet (although I have the proper line in stock) and as I can feel good pressure in the lines I don't think the prob is there, but I'll keep an eye on it.

About the clamp at the hose between the plenum camber and the air filter housing:
I've found a short ratchet (with 1/4" square) and a long 7mm socket is well suited for this limited space.

Inge K. wrote:About the clamp at the hose between the plenum camber and the air filter housing:
I've found a short ratchet (with 1/4" square) and a long 7mm socket is well suited for this limited space.

That's exactly what I use. Great minds think alike

RicK G wrote:

Inge K. wrote:About the clamp at the hose between the plenum camber and the air filter housing:
I've found a short ratchet (with 1/4" square) and a long 7mm socket is well suited for this limited space.

That's exactly what I use. Great minds think alike

+1
May as well jump on the bandwagon.
Anyone else like to join?

Me too  

See it's so obvious just how superior BMW rides are, we all know the right way