Bringing up an old thread because it showed up when I searched for my issue. I, too, have a leak coming out of the rear swingarm weep hole. And yes, it is a leak, not a few drops...the whole rear final drive area is covered with oil. The bike is less than a year old, just under 17k miles, and ridden almost exclusively on the street. I already had to replace a different seal on the final drive last fall (next to the wheel/hub) for a leak.
Hopefully I can find a dealer who will work on it. My purchasing dealer has been less than helpful- it took a 3 month battle for them to fix wheel damage, then when they did, they had the spokes so bad that two were rattling loose and the wheel had terrible runout. They have made it clear they don't want to warranty anything else on the bike since I do my own maintenance (oil changes, etc.) As an auto technician for ten years I'm quite qualified, but the dealer and Yamaha disagree.