Somewhere between the carb butterfly and the intake valve, that's where the vacuum pulses. Not sure on the specifics for your engine. Some carbs already have a fitting on them for the vacuum operated fuel pumps.
Mikunis wont have one, but there should be a manifold that hooks the mikuni up to your engine... post pics of that. That would be the best place to do it. What kind of engine. Is it one of those 4 stroke lifans?
If your carb bolts directly to the intake port, probably your best bet would be to make, (or buy), a spacer with a pulse fitting in it. It might be possible to drill and tap a hole for a fitting in the carb itself, but there is a possibility that you could screw up the airflow by doing that, the spacer would be the best bet.
Thanks guys. Its a 4 stroke Yamoto 125cc pitbike engine I bought for $40au lol. Lacking compression at the moment but its a project none the less. Here's some more pics.
^notice the destroyed gasket lol^
So are you saying I can simply tap a pulse fitting directly into the intake manifold?