If it were me, i'd give Ben at Promax a call, send the carbs to them and have them "work" on them, especially if they are used. Money well spent in my book, but you can do it yourself too if you want to save some dough, are logical & methodical.

Non-stick carb gaskets, proper float levels, the correct initial & total timing & advance curve in your dizzy help tremendously!

There are some great posts about setting them up on this board, but this search engine makes it a challenge to find them sometimes.