kz650 electronic ignition advancer

I'm trying to source an electronic ignition advancer for a 79 650 LTD motor. It didn't come with an advancer so it currently has a 550 advancer. The marks are off and so the cam timing was set based on piston TDC and ignition timing is guesstimated. I'd like to avoid this uncertainty.

As far as I understand, all the 750 and 650 advancers will fit onto the crank and the timing marks will be right but the ignition timing will be different. I was thinking about getting a 1013 advancer (10-40 timing advance which is close to the 650 10-35). Another option is buying a 79 650 advancer and transferring over the 550 electronic timing cam but im not sure that it would fit like that?

I used the advancer from a spectre 750 on my kz650, seems fine.
Comparing the kettering ignition advancer, the slot that receives the crankshaft pin is rotated, nothing else is changed.

That last sentence is confusing. What do you mean? kettering?

Edit: found another listing on ebay that was hard to find for a 650 csr electronic advancer and so i grabbed that for $30. Worth it i think. Im still interested in what people have to say on this topic though.

Kettering is the specific type of ignition system used on many KZ models. It is named for its inventor, Charles Kettering, who also invented the electric starter and Freon. He was also, I believe, one of the founders of DELCO.

www.ratwell.com/mirror/users.mrbean.net.au/~rover/ketterin.htm

Ah, okay, thanks. I was just worried by the way he said the pin was rotated.

That website was an interesting read!

It's the slot in the back of the advancer that mates with the protruding pin in the crankshaft, that's the only difference between advancers.
I had the opportunity to eyeball the kettering unit and the pick-up coil unit. The spring tensions appeared identical, the dimensions of the governor arms too.
Worthwhile noting that the rubber dampers on the governor arms have to be fairly fresh for the timing to work correctly.
The spectre advancer seemed to follow the timing curve when tested with a strobe.