If AMC49 is out there, per your suggestion, I broke broke carbs apart and went through them again using MacGregor instructions. The carbs are clean and all orifices open. I bypassed the air cuts as recommended. Put all back together. New dr8ea plugs (could not get dr8es). Pilot screw 3 turns out as recommended to account for air cuts bypass. Bike ran great. After 3rd ride, bike bucked at low rpm, ran great at high rpm. Pulled plugs, coated with black carbon like soot. Figured running rich. Cleaned plugs, reinstalled, set pilot screws 1 1/2 out (leaner). Bike ran better at low rpm longer before acting up. Pulled plugs, still slightly sooty black. Will I hurt anything turning pilot screws in further? Should I go with hotter plug? Would you suspect bad coils or igniters (they look original)? Any advice would be appreciate.