well the ignition has a live feed that goes through a fuse and then goes into the right hand switch gear then it goes to the left hand swithc gear and gets either fed to the low or high beam wire dending on the switches position then it gets fed to a relay that it switched either way and then it goes to the headlight bulbs.you need to establish with a power probe or meter if the power from/to the on/off switch is there and if its getting to and from the hi/lo switch to the relay and then if its getting from the relay to the bulbs.if your anywhere near milton keynes id have a look for you.
adam bike doctor
September 2010