Unfortunately the ever popular Haynes company didn't produce a manual specifically for the KH125. However, there are workshop manuals available and they often appear on Ebay (often for silly prices).
Please note, I am not in a position to supply technical manuals or scans though there are some wiring diagrams, the odd parts microfiche and random service information that can be accessed from the contents menu on this page.
Also, I am NOT a mechanic so please don't ask me technical questions about the bikes - try bike forums such as BCF which have workshop sections.