As 350TS said, the wiring to the solenoid causes problems, it happened to me when it wouldn't start after filling up with petrol, I had lights, horn everything bar the starter running, turned out the wire to the solenoid was loose, (and bodged), where it sits just behind the vertical bracing on the frame on the off side of the bike, once it was re attached it fired right away I have secured it with a cable tie and had no trouble since.
Reading through the forum at the time it seems to be not unusual. Here is a link to the thread, some good info from the guys on it.
http://www.ukmonster.co.uk/monster/s...highlight=wire