Does anyone know where I can get a replacement starter or recommend who could rebuild or get a rebuild kit? The bike is a 1983 500SL

I don't know for sure, but think that since early 750 monsters shared a few things Pantah, that or 620 even might be a fit. Any place that does Japanese starter repair should be able to help, since nippondenso is the most common on Ducati. If just brushes are needed there is a listing in the Ducati parts system under 851 or other early '90s model (again may work, not sure). I wrote that down somewhere, and have meant to dig it up. If I can remeber I'll post next week. Sorry meant to reply earlier, expected someone would have a firmer answer. I even have a Kawasaki part number somwhere for brushes that can be made to fit some starters. Bug me if you are getting no answers worth while, has to be a way to fix it.

Ducati brush set for 400-900 monster (to about '96-'99?), 748-916
067050815 ****update; available, $45.50 should be holder plate and 2 brush.
Kawasaki brush plate (fits later starters I think), plate and 1 brush (need # for 2nd brush) 14079-2055.*****
hoping for good weather at Mosport.

Was it original? I had mine rewound a couple of times before replacing it with a NipponDenso that bolted straight on.

As you know on the 500SL you have to remove the timing wheel (and redo the timing on reassembly) to get to that third bolt out to get the starter off, so replacement is not as simple as it should be.