OK, I am having a case of the stupids.
When I got the bike, the dealer went over everything and told me how to drain the carb. It was obvious then, but I can't find it now! I've looked at schematics and stared at that side of the bike for too long looking for it.
If anyone has a Vulcan 800 (or probably any other vulcan) could you please describe to me where the carb drain plug is?