Thanks guys, I'll try looking at the mix. As you know The MC18 comes with the TA20 carb. When I bought this bike and tore it apart, I found the carbs to be a set of TA21 B's. I suspect that these flow a lower volume of air since the MJ and SJ sizes were both as specified for the MC18; 130, 132, 35. Anyway, the previous owner seemed to have the settings too rich since he removed the airbox, oilpump and left the oil feed nipples at the rear of the carbs open! It did'nt solve his problem though.
I filled the MJ's with lead and etched (via electrical means) the jets to be exactly 125. It solved the top-end richness but the bike is still very heavy on fuel if you putter around. the plugs DO get all coked-up after a slow-slow ride. I can't however use the same method for the SJ's to get them smaller since the wholde thing has an emulsion tube attached to them. Any help?