New Aluminium Amal Premier carb with worn out tolerances. 

I bought a new Aluminium Premier concentric, intending to swap the new no 3 slide with an existing new no 3.5 slide I already had which was the correct size for my B50, as my Commando required a new no 3, so I anticipated a simple swap. I then discovered both the new Premier slide and the new carb slide bore, was 2 thou bigger in diameter than even my worn out old Commando carb.