Since I have had the bike I have been suffering a drain on the battery. On the way I have changed the battery, reg/rectifier and cleaned up all the usual connections. What was happening was if I left the bike for a week in the garage it was a real pain to start. Hit the button and it would appear to have a flat battery. Sort of got round it by keeping it on the optimiser all the time.
Then it was pointed out to me that when I pressed the brake, the pilot light at the front would come on.
Further investigations ensued..disconnected one of the tail/brake lights showed that the front light only came on if one of the lights was disconnected.
Getting closer to the problem..
Finally took the bulb out of the socket and turned it round and refitted..problem sorted.
Have left the bike now for a week at a time and it starts ok.
This may be of some use to someone, so thought I would share.

