Motorcycle Repair: Honda CG125 1996 Headlight, honda cg125, headlight circuit

Question
Chris,
When I turn on the headlight all is fine.
When I turn on the full beam everything turns off?
Looking at the light there seems to be only 1 bulb - so I assume that the bulb is fine.
Is this a wiring issue or is there a problem with the bulb?
If it is a wiring issue are there any website with diagrams on them?
Thanks
P.S. Sorry to ask such a basic question - I've only had the bike 3 months.

Answer
Hi Gavin.
 If only the headlight went out when you hit highbeam, then I would say it was likely a bulb issue or a short in the highbeam circuit at or near the headlight itself.  However, the problem that you have is much bigger.  

 According to what you are telling me, you are getting a systemwide failure when you hit the highbeam.  This is clearly indicative of a major short.  Somewhere in that system where the circuit for the highbeams crosses, or comes in contact, with a main circuit on the bike, there is an open short.  Check your wiring both visually and with a meter.

 You may want to check the bulb as well.  If this bike is set up with all of the lighting running through the headlight circuit, then a burned out high beam could cause the problem as well, but I don't believe that this is the most likely cause.

Let me know what you find.
Good luck.
FALCON