Dim Headlight & low voltage

[cadyfatcat]

Greetings!

This board is a wonderful resource and I'm happy to have found it. I have owned a Honda CH80 for about 7 years now, put on about 6k miles, and it's always been very reliable - and it still is. However, the headlight never worked well, and currently it hardly works at all. I never rode it at night so this was never a problem. But now I want to commute back from work with it, and it will be dark most of the time.

Anyway the following will explain the symptoms and what I've done thus far to mend them (unsuccessfully)

The headlight and the dashboard lights are extremely dim. Every other electrical thing on the bike works perfectly. I have no issues with the battery, all blinkers and tail light are strong. This made me believe the bulb was the issue. I took off the headlight and attached a 25 watt 12v bulb (brand new) and it was also very dim. I then measured the voltage coming through to the headlight and it was 4.5V, and when I revved the engine the voltage actually decreased a bit to around 4V.

So I am a bit confused as to what the issue is, I'm no electrical wiz but I assume I should be getting 12V there. If 12V isn't coming through but everything else is working fine (except the dashboard lights) could the alternator be the problem? I have seen mention of the regulator on other posts but failure of the regulator would probably let too much power through...

Any help would be greatly appreciated

Thanks!

[cruzingratiot]

you say you have no issues with battery
did you have it checked ?
I have had batterys last years and ones last only days

you should check voltage at battery with digital volt meter
the voltage should be higher when running at a increased idle
than with the bike not running

if voltage is lower when running you have a charging system problem
the shop manual will help you on how to diagnose what is wrong
down loadable here on site


Honda Aero 80 Service Manual (NH80), 1983 - 1984
viewtopic.php?f=11&t=19041

Honda Elite 80 Service Manual, 1985 - 2002
viewtopic.php?f=11&t=8555

Honda Service and Owners Manuals
viewforum.php?f=11

[motormike]

I would test the stator to determine it's status,..
as you know that only 4.5 V is making it to the headlight socket.
I have seen many times on various machines the symptom of dim lights due to faulty regulator/rectifier, so...
I bet that is what has failed on yours.
Still, could be stator, so start there if you don't have a spare reg/rec laying around.
If you DO have a spare, throw it in...
Of course, loose ground connections are always suspect...idk.