This evening, I did it!  Managed to get some argon co2 mix and with the 0.8 stainless on my mig, gave it a go! I'd been helping a friend today on some welding on their 2cv project, my God what a horrendous pile of scrap, like trying to weld tin foil! Was so nice welding on 1.5mm steel and not burning through Anyway, this piece was 23 quid or so from a company on Ebay I sliced it in half then kept slicing until i ended up with a gap of 1" between the branches, then welded er up! I actually didn't photo this on account of loosing the will, as the exhaust section kept knocking my tool board pots with nuts and bolts off. But after about 20 trips under the car, test fitting and cutting, I welded it to the other stainless section.  I haven't got any flap discs to clean up my messy welds, but not fussed really!  Test fitted it once more, it's a little tight so I might grind a little off the chassis lip to avoid any clanging. Clamps are on order then I can get the whole system tightened up. I will also clean up those messy welds

Played around with it more, starting to think it might really just be the exhaust? Hopefully not a cracked manifold... The noise is just a bit unusual, but it runs too well to be something serious? The backfiring through the carb may just be that I've failed to dial the timing in properly, as another issue I've had is all my plug leads ended up too short as the repro cap I have is 90 degrees offset to the original one... You and me both, I don't like the Solex, this one is very basic and doesn't even have an accelerator pump. I'm intentionally avoiding disturbing it as new parts are hard to come by. I'm pretty confident as I just reused the old factory marks, I've checked the timing using the WSM method and it seems fine, TDC on exhaust stroke corresponds to point of balance. Also checked the valve clearances again, all okay.

I just wanted to avoid this all together so just used stainless wire and argoshield gas. But that's a very neat trick

Haha thanks, it's been a very long battle, I'm tired and all I want to do is drive the thing

I think so, any boc place should exchange them. Mind you I've been using those little 600g bottles

Yes. Both desktop and phone (android) would previously reject the (boring) standard stuff. Now that is all that is available on both. I am saddened by this ...

How confident are you of the valve timing? Fairly straightforward to check with the rocker over off…..

Hmmmm…. Still here on my phone….. along with various others My phone also offers the standard (boring) iPhone ones but this forum doesn’t accept them…. Though others using the same software do.  It’s witchcraft I tell you…..

The badges say 2000 and the running gear is clearly big saloon.  Not that I'm interested in buying any of it

Good progress. That rattle sounds awful on my phone speaker though! Have you got an angry seagull trapped under the rocker cover? Spitting back through the carb mouth often indicates lean mixture but I know nothing about Solex carbs and their peculiarities. Apologies for being no help whatsoever