Nowadays I just use a needle file and I slot the bore. Then I press fit in a thick brass plate. Similar to how I did this on the motor-side of a carb:
It's a lot of work to do by hand. On the BST40 you'd want it on the intake side. A lot of filing and shaping of the part. There's a lot of pressure there so you don't want to do something weak, like simply glueing it. BTDT. It will get sucked in.