Headlight drains voltage

[Guest]

1981 GS450T, I've had some electrical problems which led to replacing my battery and R/R. It's doing much better now; 12.5v at idle and about 13.0v at 3500 rpm WITH THE HEADLIGHT OFF. When I turn it on the revved voltage is about 11.5v and idle is much lower. What can I do to fix this? New bulb? New headlight unit? I will check the voltage at the headlight itself but wanted to get this out there first. Thanks.

[Griffin]

Have you done preliminary electrical checks? POSPlayer has a quick checklist to start.

Don't assume that since your battery is new it is good. 99% of the time, it is. But once in a while, you'll get a bad one from the factory (particularly if it is an inexpensive wet cell type).

Go through all of this first, then report your results:

http://www.thegsresources.com/_forum/showthread.php?164993-Charging-System-QUICK-TEST&p=1272192#post1272192

If that all checks out, you can progress to this:

http://www.thegsresources.com/_forum/showthread.php?152769-GS-Charging-System-Health&p=1138531#post1138531

[Nessism]

Hope you rewired the charging system to bypass the factory harness. Something tells me you didn't...

[posplayr]

You are charging very poorly. I would not want to hazard a guess why without all 6 of the quick test numbers.

[JTGS850GL]

Your headlight is not the problem. Your charging system is failing. The problem could be in several locations. You need to go through the Quick Test as on posplayr's signature and report back what the results are of EVERY test item.