Davenport. Iowa located in eastern Iowa on I-80
This Labor Day Weekend the swap meet and vintage dirt track races happens . The website below has all the info you need.
http://chiefblackhawk.org/Lots of bikes in the lots and in the swap meet. The fairgrounds are 30 to 40 acres and are filled with vendors. Food and drink vendors, too.
I suggest going Friday and Saturday as by Sunday they are packing up.
Be sure to enter the building West of the grandstand. Theme bikes for the year are in there.(Choppers, bobbers, rat bikes, customs from the 70's)
The dirt track races are on Friday night. I love the smell of two stroke racing bikes. I love the sounds of XR750s and big British twins.
I try to go both days, I always miss something on Friday so Saturday is good too.
Steve