I think that the mechanism is the same as the 2001 kdx 125.
Not sure btw!
I don't think they are....if I remember correctly, our member "queen of spodes" recently confirmed they're different, and won't work on an '89 KX125.
Is there somewhere instructions for setting up the KIPS in the cylinder barrel of a '89 125 KX?
you can try using the sites "search" option....or start browsing through the "KX125/KX250" forum...I'm pretty sure I've seen a thread that has a walkthrough in the past....but don't hold me on that.