Went to start the bike tonight (CB400) and noticed the headlight didn't come on with the ignition turned on. Wasn't the globe or the fuse. Stuffed around a bit and started engine a few times and eventually they came on so I headed off. Later when I was about to come home same thing happened. This time I just started the bike and about 30 seconds later the lights came on. Stopped for petrol and this time it started up with the light working straight away. Next stop was for about 20 minutes and same problem with them starting up after a minute. Is it possible that there is something wrong with the battery? Though maybe it isnt holding its charge and the lights kicking in when it is running and charging - but would it still be able to start the bike if this is the case? All other lights work. Any suggestions of possible simple problems are welcome as I cant really afford to take it somewhere to get it checked out unless it is really necessary.