Is the starter motor really the problem?
If so, why not rebuild it?
If for some reason that is not possible, put the brand name and manufactirer's number (both usually embossed on the starter case) in your favorite search engine and see what comes up.
Why do you want a non-stock starter?
1982 KZ1000 LTD parts donor
1981 KZ1000 LTD awaiting resurrection
2000 ZRX1100 not ridden enough
