Yes, it could be poor electrical connections/resistance related. Have you tried testing the coils resistance at both primary and secondary sides? Have you inspected the plug caps? How does the regulator test at various rpm's? All connectors and the battery must be in good shape to do the tests.
If all are OK, there's a couple more things to check.
Be sure the venting is clear. Gas cap and any float bowl vent lines or the float chamber vent passages themselves. Heat generally aggravates a poor venting problem.
I would also verify the entire pilot circuit is clean and the float levels are correct. Dirty air jets, at the filter side of carb body entrance, could be varnished up a little and creating a "rich" problem once hot and at idle. Poorly operating choke circuit could cause your problem. Takes only one carb to cause this problem.
If all are OK, there's a couple more things to check.
Be sure the venting is clear. Gas cap and any float bowl vent lines or the float chamber vent passages themselves. Heat generally aggravates a poor venting problem.
I would also verify the entire pilot circuit is clean and the float levels are correct. Dirty air jets, at the filter side of carb body entrance, could be varnished up a little and creating a "rich" problem once hot and at idle. Poorly operating choke circuit could cause your problem. Takes only one carb to cause this problem.