We're sure it's not the crossover.
I forgot, about those crossover tube where it connects into the manifold, it's starting to dry rot. It's not bad enough to let in air but does anyone sell those manifolds new?

 

There's 2 crossover tubes of sorts, One is the aluminum one between the manifolds. The other one is the small black tube between the carbs. It is about 1/4 diameter or so and about 2.5 inches long.

 

The crossover we are talking about is not the metal tube that goes between the intakes. We are talking about the short piece of 5/16 hose that actually goes on the carbs. This hose lets the right side carb pull fuel from the left side carb's bowl when the choke is on.

What kind of air filter are you running? stock, K&N, Toomey 2-n-1, etc? Are you running an air box lid? Air box lid snorkel? My play banshee has a special filter that allows so much air that the choke won't work properly.

Have you tried a squirt of carb cleaner or either?

Wyo, I just looked back over the page and you posted about the crossovers before I finished typing, sorry to repeat.