Maybe a simple answer - I swear I've asked this question here before and got an answer - just couldn't find it.
So I swapped carbs from a Puch Newport on to a Pinto 2. It starts fine, but when I pull back on the throttle it give that deep throaty dying sound. If I accellerate slowly, it gets up to full speed. I had this problem with a Ciao a while back, and I think I fixed it by adjusting the mix screws on the outside of the carb - though I can't remember.
What's the cause/fix of this?