I would also try to find a newer 690 so that you avoid the problems that were had with the old style speedometer. Again, I created a poll (both on SupermotoJunkie and on AdvRider). The SupermotoJunkie poll showed a 73% failure rate on the old dashes out of 40 voters!
To me this was symptomatic of a speedometer that wasn't built to handle the big time vibrations that the 690 thumper was putting out. I believe they got it fixed on the newer versions, but it was a real headache on the older ones.