are 02 kdx forks really kx forks from 1988?

A very astute observation ! I happen to still have my '88 KX --sold my '98 to get the KDX [big mistake]. The forks are almost identical. The KX claims just a bit more travel and I think the rebound rod is just that much longer to allow it. The hydraulic bottoming cylinder [KDX] is different from the KXs tapered bottoming cone. The rest should all be interchangeable ! So then, WHY is it so darn difficult to get the KDX to handle decently when that old KX is so smooth ?????????????