Seatte actually has a huge female meetup following for motorcycles. I've never attended though, as I usually just ride with friends I've met so far. But they have multiple rides a week.
http://www.meetup.com/WWLadyRiders/
Jun 06, 2014
Starting a group by: Lynn - Florida
I had great luck with Meetup.com when I was looking to find ladies to ride with in my area. Just be careful how you title your group name. Mine was "Motorcycles-Girls Just Wanna Have Fun". I was innocently copying Cindy Lauper's song but found the title attracted some unwanted inquiries.