Motors were revved up as several Harley-Davidson bikers spent a weekend in early September riding the roads and touring the sights in Door County.    They were welcomed for their weekend stay at the Birchwood Lodge in Sister Bay, where they enjoyed the pools, accommodations, and close proximity to restaurants and the waterfront  park.   Several of them commented that the rooms at Birchwood lodge were exceptionally clean and the staff was so nice.   Throughout the year,  Birchwood Lodge is always happy to host a variety of  groups large and small.   Plan your family reunion, girls getaway, club or group trip to the Birchwood Lodge.