Mystery gasket

[jphillips138845]

I was removing the Halls Sensor on my 92 100GS to replace timing chain cover gasket. When I pulled the can out I noticed what appeared to be a small gasket fall to the floor. The gasket or what ever it is, is approx. 3/4 X 1/2 inches, rubber in texture and appears some what transparent. I am unable to find it in a manual, the dealer could not identfy it based on my description. I thought when it fell in the floor it would be obvious where it came from, not so. I am to the point where a good guess might help-thanks

[20774]

I believe this picture shows the Hall Effect unit...there's an o-ring behind the sensor, not a gasket. Is this the first time the sensor has been off? Maybe a PO installed the wrong item.

http://www.realoem.com/bmw/showparts.do?model=0488&mospid=47930&btnr=12_0776&hg=12&fg=05

[jphillips138845]

Yes, first time unit has been off and I saw the O ring. Thanks for the link, I had saved a pretty much in detail procedure of the can repair and nowhere did it mention the gasket. I had posted the question on a UK site also and no one could identfy the gasket. You may be right, someone could have goofed during assembling the bike. I think I will contect the battery and try firing it up.