The bike has miles on it, most of which were put there by myself or my father. He owned it since '99 and I purchased it from him about 8 years ago when he bough his K1200LT. The tank was shiny and clean, with minimal granular debris in the bottom which was cleaned out when the pump was replaced. The bike ran like new until this issue and has been maintained by myself on schedule.
The fuel pump had been whining for 2 seasons, at increasing decibels, and when the bike was left out in the rain by yours truly some water got into the tank because I was foolish enough to open the fuel fill cap while there was still water that had not drained from around the edges. I didn't know how much water had entered the tank, but had assumed somewhere near 1/4 cup of rainwater, so I added some fresh fuel and dry-gas and drove it. I made a 30 mile round trip when it started giving issues near home, with the fuel pump screaming at me from inside the tank. The bike would hardly maintain 30 mph and the throttle seemed more of a suggestion than a user interface. I turned around 2 miles away and crawled home, took my truck to work that day. To this moment the repairs for this issue include a brand-new fuel pump and filter, fully drained fuel tank (removed from bike, inverted, rinsed with fresh fuel and debris cleaned with clean dry rags. With a new pump, filter, clean/clear non-ethanol gas, and the lines flushed with new fluel to the hard-line inside the tank (tomorrow it's going to be pull the line off at the back end of the injection manifold and flush the new fuel that far), there has been no improvement in the symptoms except that the pump is substantially quieter and the bike will at least idle as long as the choke does not go beyond about 35% (cannot go to mid-stop) and the throttle is not touched whatsoever.
I'm thinking the injectors were damaged from the water and aren't functioning properly, or picked up debris at some point during the diagnostic/repair.
I can hear what sounds like one of the injectors, possibly two, but with the bike running I am unable to isolate with much confidence. After flushing the line tomorrow I'm going to try to remove the injectors and turn them on the injection manifold away from the bike so that I can see the individual spray patterns. The easiest answer is that one or more will have a terrible pattern or none at all. Any further suggestions or diagnostic tips are appreciated.
*This post was started new from the "Fuel Pump" post as it's gone beyond the scope of the OP topic*