Strange missing

[Cavman11]

I have a 1973 CB750. I have recently ran into a problem in how it acts like it is not getting enough fuel. I can start riding and it runs fine. Starts right up and purrs for awhile. Then it starts acting like it is not getting enough fuel. Sometimes it will run like that for a short time then go back to running fine. Other times it will run like that till I get home. Usually after setting overnight it will start right up the next day. I tried switching to a electronic ignition and although it does seem to run better when it runs it still acts like it is not getting fuel. Any ideas on what could be the problem?

 

[dirtdigger]

start closing the choke while it is running bad, if it picks up a bit then you are lean/running out of fuel, if it doesnt help or runs worse then its rich or not a fuel related issue. Also pop the fuel cap open see if it helps, the tank may not be venting which doesnt allow fuel to flow. Did you replace the coils/ wires when you went to electronic ignition?