A motorcycle fire in Montauk Monday afternoon destroyed not only the bike, but also the storage unit it was in.The Montauk Fire Department received a call from the Rough Riders condominium complex at about 2:30 p.m. They found both the motorcycle and a 40-foot storage container next to the complex’s sewage treatment facility in flames. Vinnie Franzone, the first assistant chief, said a condominium resident was putting his motorcycle away when it backfired through the carburetor instead of the exhaust and erupted in flames. “The owner of the bike tried to put it out as we were coming. It was in flames by then,” the chief said. Flames were shooting through the roof of the storage unit when he arrived. The 2002 Yamaha had been used frequently this fall, said Tom Baker, an East Hampton Town fire marshal who investigated. He said the owner was about to store it for the winter. It took firefighters about 15 minutes to extinguish the blaze. The bike was totaled and the shed destroyed, though some of the tools and other contents inside it were saved. About 35 firefighters responded. No injuries were reported.