... just to shed some light onto it: This guys from Germany works on the in-line 8 to use it in a sidecar. Of course you would not mount it into a solo-bike. I´ll try to update, yet this will take some time for sure.
Z1300 A1/ KZT30AG built 1979
frame KZT30A 004285
engine KZT30A 000288
location: borderland-triangle France/ Germany/ Switzerland, Europe