Is it one coil in there? It would make sense I guess. It stalled a few times when I first got it, been riding it mostly in good weather since and last week a lot of rain, although I haven't been riding in rain, but roads have been really wet 
I've heared about the stock Buell/Sportster coils that go for a few bucks on eBay and should work also.
Don't recall you mentioning the vintage of your R65. Mine's a 1981. The bike had issues with the ignition when I bought it but those problems helped me negotiate on the price.
My '81 had the original BMW
single coil with two plug leads. Some Beemers have/had twin coils. Suggest you research the "lost spark" operation of the BMW ignition before you venture too far afield. The eBay items
might work. Maybe. I replaced my Crack-O-Matic with the "drop in, dead simple" Dyna unit from Rick Jones. It's the
hook up these days on BMWs.
The plug wires and caps were OEM and ratty so those were replaced with the kit from Mike's XS
http://www.mikesxs.net/ for something like twelve bucks. NGK caps, goods wires and terminals. I also had him toss in the correct sparklers for just a few extra bucks.
"Buell" and "should work" don't always feed the bulldog, if you get my drift. Not a great rep for reliability. Could be why they only cost "a few bucks". Just my opinion, boys. No offense meant to the mid-life crisis
Hardley-
Dressed folk.