The bride and groom will have written their own vows or with help from their wedding officient, who is most likely a biker himself. Rev. Chip suggests using phrases like "brothers/sisters in the wind" as well as tongue-in-cheek things like, "shiny side up", "dirty side down", or "the starting fluid of love", etc.
Once the bikers are pronounced husband and wife, the motorcycles are reved up again as the bride and groom walk up the aisle together. Then it's PARTY TIME!
Here's an idea from Rev Chip: "I did one in Sayler Park last summer where ALL the wedding party entered on bikes in staggered parade formation, with the exception of the Groom & the Best Man, who rode in first with me, and the bride, who rode in last. She had her wedding gown modified with a full length slit in the front and back with lace shorts underneath! You need a BIG open field and a good PA system for a ceremony like that."
If you expect alot of guests to arrive on their motorcycles, have space available for them to sit on their bikes during the ceremony.
Or how about setting up seating in a circle with the bikes surrounding the circle with the bride and groom in the center - ahhh, a circle of love.
If you can and they want, give guests a ride to their seats.
Get the guests involved and have a mini poker run on the way to the reception. The winning hand could get the first dance with the bride after the groom.