Vacuum set equally across three carbs, colortuned each cylinder (what a wonderful tool!) except no 4 as I simply cannot get to the adjustment screw - running a little rich, so no biggie. All electrics work properly and it stops well.
So I went for another test ride and it runs lovely however, a slight ticking at idle on front LH side of the cylinder head cover turned at higher revs into a noise that sounded like a chain rattling. ... AAARGH!
I am letting it cool down and then I will whip off the cover to see what is happening.