Well, I rebuilt the carb, replaced fuel lines & filter, new plugs, new thermostat & diaphragm and fuel line & bulb to the tank and....it runs about the same. Actually, above 1500 rpm it runs like a sewing machine. Below that, an 80's Harley.
I check the manual and ended up finding a problem with the top CDM, so I ordered a replacement that should be in Friday. It actually makes sense because i was getting much worse fouling in the top cylinder at idle which would correspond to a bad CDM.
I don't know enough about CDMs but apparently there can be failure that only affects low rpm operation.