I can't seem to find a service manual for my newly-acquired 2003 KX 125. I checked for Clymer's; no luck, they don't seem to have one published for my bike.
Your bike is still too new for Clymer to have produced a manual yet. The only option is a Kawasaki factory manual, available from your dealer or the link given above.
I have a 2003 KX 250 and I just went to my local dealer and purchased one through them. It is the factory Kawasaki Service Manual. No complaints and about the same price as a Clymer.