1983 goldwing 1100 fouling

I recently purchased an 83 Gold wing and it stumbles under
acceleration and fouls the plugs on the left side no 2 & 4 cylinders.
I've cleaned the carburetors. Could a plugged accelerator pump
passage to the left bank cause it to foul out? I noticed dirt in the
accelerator pump area when I cleaned it.

Any suggestions would be appreciated, as I'm a beginner shade tree
mechanic.

 

dirt out of no where

i had this xs 650 and the fuel filter kept getting blocked, the tank was cleen, i found that the tube from the tank to the filter was rotting on the inside and breaking up, lucky it was befor the filter,,, on the note of that xs650 i baught it for 200 pounds, it had been hard tailed by a joker, the swing arm bearings had been worn out, so he removed the shockers and welded in bars, the back wheel was tracking left so it went round roundabouts fast, but you had to pull it down to go left, btw, it had the same front brakes as my rd350lc sold it for parts it made 150quid profit