Motorcycle Repair: Super B, air fuel mixture, open tubes

Question
Mike, I'm looking at the back side of this carb and right below the "S&S" marking is a hole that is open to the outside. In the base of the hole is a smaller hole, maybe .050" or so which leads to the cross drilling that goes down to the main jet emulsifier. That's all, no plug, no opening to the throat, or to the idle circuit, and I'm thinking this can't possibly be right.

The bike starts well but with the idle mixture screw all the way in. It transitions to the intermediate circuit very poorly and apparently leans out. At WOT it does well but around town it fouls the plugs. And it takes a very long time to warm up.

It's an S&S Super B, has a casting number "81" below the "B" and a "3" under the open hole I mentioned which is in front of the 81, also "J1844" on the top of the carb. It's being used on a piglet, 1973 1000cc with 10:1 pistons, open tubes and possibly hot cams.

Thanks for any insight you can give me.
Jim

Answer
If the idle mixture screw is all the say in then you have a problem with the carb. I would suggest removing it and rubuilding it as well as cleaning it.
One you have that done then install the carb and open the idle acrew around 1.5 turns. Test ride the bike. If you are to lean below 2500 RPM then you need a bigger intermediate jet. At full throttle if you are fouling plugs then you need a smaller jet. Remember to adjust the air/fuel mixture screw anytime you make a change
Good luck and happy riding
Mike