Jeff:

DavidM is right, but more specifically it's the "Sportster" 65 engine. And it's a late production example, it either came with the remote needle or someone replaced several parts.

If you have to have a front mounted needle valve, you can replace the mixture disc with the earlier type that accepts a threaded pipe with the needle valve, or just replace the entire carb. See pictures. The parts are available from MECoA, not too expensive. They will help you to pick the right parts if you give them a call.

Bill.