Compatible starters w/ 1982 KZ250

Do any of you know if any other models have starter motors that are compatible with the 1982 KZ250? The one on my resto project is totally burnt out and shot. The starter motor on my donor bike, the 1980 KZ250, isn't compatible.

Any ideas on where to get a decent low-price replacement? If there are other years/models that will fit the 1982 KZ250, that will give me more to search for on eBay.

Thanks,
Chris