5.3 volts at headlight on high and low beam

[justinkr58]

any ideas? thisis constant even when reved. the brake is also out. but the blinkers work.

[SpudRider]

Originally Posted by justinkr58

any ideas? thisis constant even when reved. the brake is also out. but the blinkers work.

I encourage you to check whether you tail light bulb is extinguished. However, I am puzzled how your headlight voltage has dropped to 5.3 volts. :?:

Spud

[justinkr58]

yea it worked yesterday /// idk whats up.

[Weldangrind]

I've been thinking about this, and I don't suspect the stator or the regulator, since the bike runs and the blinkers work.

When you test for voltage, are you probing the ground connector for the headlight, or are you using a metal surface (meaning frame ground)? Try a reading again, and this time use the negative post on the battery.

Also, it seems more than coincidental that the headlight dimmer and turn signal switch are located in the same housing. Any damage to the harness for the controls? Have you located the connector to see if a pin isn't properly engaged? Any corrosion?

[BillR]

Originally Posted by justinkr58

any ideas? thisis constant even when reved. the brake is also out. but the blinkers work.

Welcome to my world... :wink:
My GY-5 did the same thing and I never could figure it out.
Mine would read somewhere in the neighborhood of 10-11 volts at start-up. After a bit of idling, a noticable drop in the amount of light and voltage would drop to 5-6 volts.
I even took the wire loom "apart" and traced all the wires. No breaks or loose connections. For some reason, the headlight was wired directly to the stator (way I got it).
I checked the charging voltage at the battery when this happened. Start the bike...voltage 13-14 volts, as expected. After about 1 minute, the voltage would drop to 12.5 or so...battery charged up?? and the headlight would dim.
The only thing that came to mind was the voltage regulator was somehow dropping the voltage when the battery topped up.
Finally went with a switch relay and ran the headlight off the battery.
{quote="WeldandGrind"]When you test for voltage, are you probing the ground connector for the headlight, or are you using a metal surface (meaning frame ground)? Try a reading again, and this time use the negative post on the battery. [/quote]
Very good advice. I was using the wires to the headlight for ground. Bit of a different reading when I used the negative terminal. Didn't help with fixing the problem.
Good luck,
Bill R

[Weldangrind]

IIRC, the headlight has a dedicated lighting coil, and that's why it's wired directly. I've been studying a schematic for an old Honda, and the lead from the lighting coil travels through the dimmer and then straight to the headlight. In the case of the old Honda, the battery isn't related; to power the headlight off of the battery would be an additional strain on the other stator winding.

If the battery voltage is low at the headlight (and there is a dedicated lighting coil in the stator), there could be a problem at the winding, the wire to the dimmer, the headlight connector or the ground. When I recommended checking with the negative probe at the negative battery terminal, that was for comparison purposes. If the voltage reading drops significantly when probing the gound connector at the headlight, the ground is poor. That's usually solved by adding a ground strap from the engine to the frame.