Having problems with 85 K100RT running not running on #1&4 cylinders. Very similar to what I read on what I believe it was Chocolate Frog's systems. I believe his problem was two bad injectors. I have fire to all spark plugs/cylinders. I can pull the #1  plug wires and no difference in running. Can pull 2 or 3 wires and it kills bike.
I have switched coils and no difference. Tried different plug wires-no difference. Pulled all the injectors, hooked to voltage and sprayed carb cleaner through them and verified they are opening and good stream discharging through them. I have checked each injector lead with a LED lamp and verified injectors are getting a signal. After reassembly took steposcope (bike running)and listen to each injector and could hear each clicking as if they were opening and closing. I have checked under tank frame ground, ignition unit and hall sensor connections. Each one were clean as a whistle and appeared no fault. I was wanting to trouble hall sensors but didn't quiet follow/understand logic from flow chart. Any suggestions would be greatly appreciated.

If you swapped coils and the problem remains at 1 and 4 then coils are good and problem is in Hall Effect Sensors [HES] or in plug leads.

However plug leads unlikely to both go at same time and much more likely it's HES related. The HES wire goes up over the radiator and worth checking the connector to the loom and also the wire itself as the heat can cause it to fail after 30 odd years. If you have a spare HES plate or set it's worth swapping them.

Have you opened up the HES cover to see what's in there?

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i know this might sound like a stupid answer, but my other half had a similar problem and found that it would only run when the throttle was turned and the starter on. he found out by trial and error that the fuses were loose. The engine wouldnt idle or it would cut out and sound like a bag of spanners and would only fire up and not lose power when the starter is pushed... it turned out to be a pants connection on the fuse.... his words, not mine

Having been through what you are describing myself, and knowing how maddening it can be, I'd suggest that in addition to checking the various plugs, grounds, etc., that you also clean them with De-Oxit to be sure.  Sometimes even if they look clean, they can still be a problem.  

I agree with Olaf that your problem sounds like it's with the Hall Effect Sensors (HES).  However, I'd also double check (after cleaning both sides with De-Oxit) that the plug to your ICU (under the tank, at the head stock) is firmly and completely seated.  I had a non-firing 1-4 cylinder situation and found that the plug was firmly attached on one side but knocked slightly loose on the other and that this was my issue.  Of course I only discovered this after several weeks of testing everything else under the sun.  Best of luck!

Have not pulled HES cover, do not have spare. After I pull cover how do I check? LED lamp on pins two & five? I'm I in fifth gear and turning motor over to check signal? If HES is removed is this where I reset signal at "X" degrees before TDC? (Don't remember exactly what timing is set at off top of my head)

Hall Sensor Test Procedure for Oilheads.  Is the same for Bricks.
Making a Hall Sensor Test Rig.  Also a similar test rig is detailed in this K100-forum post

KJustin wrote:Having been through what you are describing myself, and knowing how maddening it can be, I'd suggest that in addition to checking the various plugs, grounds, etc., that you also clean them with De-Oxit to be sure.  Sometimes even if they look clean, they can still be a problem.  

I agree with Olaf that your problem sounds like it's with the Hall Effect Sensors (HES).  However, I'd also double check (after cleaning both sides with De-Oxit) that the plug to your ICU (under the tank, at the head stock) is firmly and completely seated.  I had a non-firing 1-4 cylinder situation and found that the plug was firmly attached on one side but knocked slightly loose on the other and that this was my issue.  Of course I only discovered this after several weeks of testing everything else under the sun.  Best of luck!

This seems to be a common issue too. Now I tell people to go to this fix the plug connection first as its easy, no parts required.