The exhaust is clear - no real carbon. I soaked it in carb/parts cleaner for two days as a precaution.
I think I have everything squared away. I am running a 66 main jet with this Miniky clone carb and 60cc Niche kit, stock filter. It takes a minute or two to warm up/clear out. Once it is warmed up, top speed is just beyond 30 mph (speedo pegged) and it has a slight bog at the very top depending on the circumstances - i.e., level or down hill. I think that this tells me that I'm not in danger of running too lean. I don't have a temp gauge, only a laser thermometer - but I don't know what a good head temperature is anyway. Bottom line is that I think it is running very good - very quick.
I also discovered something else. In the beginning I was having issues of intermittent shutting off. I chased the carb/fuel (trying two clone carbs) and electrical. I even replaced crank seals as a routine precaution. The problem seemed to improve when I changed out the lighting coil, but I still was having a random shut down.
The other day when I yet again tried a new jet, I noticed that the float needle was sticking inside the seat. I happened to have two of these Miniky carbs and when I looked at the other one.....same sticking needle valve. A sticking valve could easily have been the problem all along. I have clear line and inline fuel filter, and while it always appeared to have fuel, I could have been mistaken.
Here is where I'm at now: I polished the float valve seat and tried cleaning the needle very well. It now falls out of the seat as expected. I have yet to put serious drive time on the street - waiting on that PA title.... I will do a plug chop this weekend to see if I can confirm jetting success.