The biggest jump in the Top 40 -- from No. 54 to No. 35 -- was registered by the Bill Medley-Jennifer Warnes duet The Time of My Life, which is helping to turn the sound track LP from the movie Dirty Dancing into a surprise hit. Dirty Dancing, which jumped from No. 12 to No. 7 this week, is a smart mix of `60s classics (including the Ronettes' Be My Baby), contemporary dance-pop (The Time of My Life) and remakes of `60s hits by contemporary artists.