After disconnecting the fuel pump you should have had the carbs set up properly to assure good running. If they were adjusted to compensate for the "over-pressure" of the pump then it would run like crap with it disconnected.

I doubt that any bike that came from the factory with the dellortos' installed had a fuel pump.

My .002

remember that like Mikuni carbs, Dellortos have different size float needle orifices, depending on "pump or non pump" applications.
pump applications use smaller orifices than non pump carbs

both the Weber & dellortos & Mikunis, need a "bleed" jet in the return line to tank to combat pump overfeed (pressure) this is easily accomplished by using a y pipe with a #60 primary jet threaded into the pipe that goes to tank "return" line.

we have had excellent results replacing the stock fuel pump with the inexpensive Mikuni single feed vacumn pump as well. smaller, less likely to overwhelm floats, and much cheaper than replacement electric pump. still has ample volume for those bigmouth 40's you guys want to run.

on a weber that continually floods, you need to check for debris in float chamber, and a piched or blocked return line 1st thing

tony