"Stone" was the best motorcycle "cult" movie ever made, full stop. "Worlds Fastest Indian" is certainly the best Motorcycle "general interest" movie ever made.
Mad Max was interesting, not a biker film, (in fact anti-biker is more like it) but the bikes were quite well engineered stunt bikes, I almost bought the remains of one of the few CB750 based bikes at a swap meet last year, it was a specially modified Norton frame and I remembered the bike from the movie, it was quite a trick looking "Cafe racer".
"Easy Rider" was just a bunch of contrived Hollywood bull#$%* to entertain the drugged out morons of the era, it had nothing to do with bikes, but rather, it was about a couple of hippie drug dealers on choppers travelling from town to town selling their #$%*. If they were driving cars, we'd all be cheering for the rednecks!
Beautiful bikes (I actually touched one of the "Captain America" bikes in Madame Tussauds waxworks in London in 1974) but the movie was rubbish. (IMHO) Cheers, Terry.