Before sending it back to Japan, and also getting confused by all of our recommendations, I suggest you look for someone at your club that has experience on YS. Not necessarily needs to be cdi proficient, but with general knowledge on how the DZ system works. Have him take a crack on your engine, and explain the ins & outs of the engine to you. If he knows how the basic DZ system works, the cdi is just an additional element that is not that though to figure out.

You will not be benefiting from anything by sending the engine back to Japan, unless the engine indeed needs repair.

Adrian