Hello All,
Well, I've just bought a kilometer per hour speedometer from BMW Meyer, w=715 and a 34/11 3.09 final drive from MotoGo Dojo from that popular on-line auction site. The listing for the diff says the bike it came off only had 12000 miles on it, and the photos of the splines looked OK to me, but what do I know (not much). BMW Meyer certainly had a few speedometers for sale, nice to have some choice. Their web-site say they've been disassembled and cleaned.
I got the 715 speedo for several reasons, one being that BMW Meyer confirms the speedo is for a 34/11 diff so I suppose that's something. That handy little JPEG table suggests the W number should be 711, but I'm not sure a difference of 4 is going to cause too much trouble. The 711 speedos that BMW Meyer did have didn't appeal for various reasons.
Cost about $1200 Aus (with postage), give or take, split roughly equally between the diff and the speedo, or about $800 US.
Cheers,
Keith