LYNN – Thousands of bikers are expected to gather in Everett on Sunday, Oct. 21, for the annual Harley Halloween Witch Ride that winds through the streets of Revere and Lynn toward the finish in Salem.The ride, which benefits the Muscular Dystrophy Association (MDA), typically attracts bikers and passengers decked out in Halloween costumes, everything from Darth Vader to Winnie the Pooh, according to MDA spokesman Jim Sharland.The motorcyclists can register on the day of the ride at Bruce Rossmeyer’s Boston Harley-Davidson, 1760 Revere Beach Parkway in Everett. Registration is from 10 a.m. to 12:30 p.m. Riders will head out at 1 p.m. for points north.Rossmeyer and Jake Curry, the MDA goodwill ambassador, will lead the way. All participants will donate $20 to the MDA at registration on Oct. 21, or save $5 per person by pre-registering at the Harley-Davidson dealership.The dealership’s Jeff Cheek is donating the $15 pre-registration fee to MDA for every new motorcycle sold prior to the event and for every HOG Chapter member who signs up at least 10 other bikers for the ride to the Witch City.Members of the Halloween planning committee are currently finalizing the ride logistics, including a new “old” route that will take the group through many streets and neighborhoods in Revere and Lynn, Sharland said. Entertainment and activities are also being coordinated for the enjoyment of bikers at the end of the ride.The MDA provides selected orthopedic equipment, free clinic visits, youth summer camp sessions, and other health-related services to Boston-area residents affected by any of the 43 known neuromuscular diseases. MDA families also receive hope that treatments and cures will be found as a result of the association’s efforts in funding research grants worldwide, Sharland said.The MDA Halloween Witch Ride is sponsored by the Boston Harley Owners Group, also known as HOG Chapter 1864, and Bruce Rossmeyer’s Harley-Davidson, with help from the Everett and Salem police departments. For more information, contact Sharland at 781-575-1881 or John Brogno at 617-389-8888.