if you do a search in youtube, you might find this video about making a bass in fm:
however, i am afraid that most of the videos on youtube seem to be tutorials on how to make a skrillex bass.
however, a skrillex bass to me isn't really a bass, although it contains some bass fundamentals.
i am a little old school, so i prefer a bass instrument to contain mostly bass fundamentals, for the purpose of creating harmonies and other syncopated events.
I envision this thread to be a place where we can share patches or discuss getting actual bass sounds out of an fm synth, (also leads, fx, whatever) and produce some knowledge about the subject for composers who like to use an FM synth as an instrument, not just a full frequency sausage effect.