We love SU carburettors- full range carburation, cold enrichment, and accelerator pump action with only 3 moving parts*. They do, however, work better when they’re clean and well maintained. These ones were anything but.
It’s easy enough to buy a rebuild kit from SU, and the bead blaster and zinc plating bath make short work of cleaning up everything. The dashpot chambers polished up nicely.
And there they are, all clean and shiny. The heat shield is a bit garish in orange, but it’s cracked as well as ugly so we’ll just order a nice new stainless steel replacement.
*excluding linkages, springs, cables, and various other totally insignificant parts that do most of the actual work.
A small obsession 
I take it the throttle shaft bushes weren’t sufficiently worn to require renewal? And what do you make of the new “Stay-Up” floats Burlen are offering? http://sucarb.co.uk/stayup-products.html
Indeed, the shaft bushes were pretty good- far too good to ream them out and fit the repair bushes that come with the rebuild kit.
I’ve not tried the new style floats yet, but I’ve never had any issues with the old style sinking.