Re the smoking, assuming the valve cap seals were refitted, they aren't perfect but do work. Some of these caps are now very poor quality and split/break up, so a good idea to take the valve cover off and check them out. Change all if any are suspect. Compression numbers are very good.
Your carb problem often hard to pin down. Small misalignments will do it. needles might be rubbing a bit and there is a small amount of adjustment in the jet mounting. With the dampers out the pistons should drop instantly at the same speed for each. spindle clamps in the centre can push on the spindles a bit even though they are designed not to. Maybe loosen and tighten these being careful not to change the carb settings. Choke settings might not have any gap between the screw and the cam. Needs a little bit and the same on each carb.
Cleaning and oiling the mechanism always a good idea, including the ball joints and pedal.