An '81 bean can ignition ... for $857.74
From what ass is he pulling these prices?
From the listing:
"BMW 1981 R100RT magneto assembly with wiring. This unit has not been tested for spark, though magnets are still strong, and bearings roll smoothly; outsides show some normal surface corrosion, insides are very clean. This unit fits all magneto ignition bikes of the 1970s & 1980s. May work on other "quirky" machines; check with your local sewing machine dealer before purchasing. Install and brag about it online! See our many discerning fans on ta'internets: http://www.advrider.com/forums/showthread.php?t=7927150
PS - That link is to THIS thread.