Carb or ignition?

I Finally got my 81 750H-2 back together. It is only firing on cylinders 1&3 until I get the rpm’s up to about 6k. Plugs 1&3 are a light tan color 2&4 are black. I cleaned the plugs and tried it but only marginally better. I checked the fuel level in the carbs using the clear tube method and they are all within spec. All the carbs were completely disassembled over the winter and cleaned in an ultrasonic cleaner and new gaskets installed. Anyone have any ideas as to where or what else I can check? Pilot screws are out 2.25 turns at the moment but once I get all 4 cylinders firing I’ll adjust those and do a sync. The valve clearances have been checked and are also within specs.

I’ve already missed 1/3 of the riding season and hopefully I’ll get this figured out very soon.

You might want to switch the coils to see if the problem follows. If it doesn't, could be the ignitor.

I decided to pull #3 spark plug cap while the bike was idling. I started getting zapped from the front brake lever. I went and tried #2 cyl and the same thing happened. Looks like a non carb issue but something to do with either the 2&3 coil wiring or a grounding issue or both. I will dive into it and see what I can find. Any pointers as the best place to start looking?

As an aside it sounds like you are on the correct track. But I wanted to add this link from Mike Nixon on the 60/40 rule of diagnostics, as I have found it to be useful.

motorcycleproject.com/text/the_60-40_rule.html

I did a little looking around on the bike last night. I discovered the coil for 2&3 wasn’t tight. The spacer and nut weren’t tight but the nut that attaches it to the frame mount was tight. I removed the coil, cleaned all mating surfaces and all is good. It’s running on all 4 cylinders.