i think i cracked my reeds on my 2003 banshee. i recently bought a set of used boysen reeds.
it runs ok but it keeps breaking up. then it will get so bad i cant ride it becouse of a bad plug(not good when your farr from home in a stuck in a snow storm) i keep changing my plugs but it keeps fouling them out. somone told me i could have a loose head(too cold to work out side so just looking for apinions)

 

When you put those reeds in, did you put the choke crossover tube that goes between the carbs back in?
What does the plugs look like when you pull them out?
When you put the reeds in, you did put the reed with the holes in it on the bottom, right (I know it sounds silly but I have seen it happen)?
Did you leave the metal backstop off?
Have you cleaned or replaced the airfilter? I saw a 2001 back in 02 that the filter had started to come apart and was causing it to run badly.
You might first try this: Under the gas tank, above the left cylinder, mounted on the frame is a box that will be silver on most but it is black if you have a LE. THe box has a wire coming out of it going to a triangle shaped plug. Unplug this and see if that cures it.