When your bashee has motor issues, a leakdown test is always good to do, so you can rule out airleaks. I would do a compession test as well. Stock banshee is around 125 psi. Your bike will run with maybe a 100psi, but will most likely be hard to start. If you past the leakdown test and have compression, you need to clean your carbs,set floats to proper height for 34mm and then maybe work on jetting and needle location and or needle jet size if these are mikuni carbs. If you bought some used carbs there's no telling what they are set up for.
Did this just happen with your old carbs or you bought it like this? Are your air filters/filter clean?