Ok, I´m assuming this is about a KH125? If it is, then I was in a smiliar situation with my 1979 KH125. It was smoking a hell of a lot. Kawasaki two strokes have a reputation for being indestructable, so It may not be the oil you´re using, you may want to consider adjusting the oil pump, that´s what sorted it for me. It smokes less now but you have to remember that old two strokes, even in perfect running order will always smoke alot. Hope this helps, I´m a complete noob to motorbikes so it may not;)