Honda 2002 CG125 electrical problem(cb100n chassis)?

Question

I have a cg125 2002 cdi electric start engine installed in a cb100n chassis+ cb100n wiring loom. My problem is that the bike will run fine for 15 miles or more with no lights on. But once i put the lights on the battery drains and the bike will cut out. If i turn off the lights the battery will recover and i can run the bike with no lights.
Generator checks...
I have measured the voltage produced :
yellow n white- 5volts ac
yellow n green - 10volts ac
white n green - 11-15 volts ac
the rectifier is working and the out put is a very low 1.5volts dc.

Any advice or info welcome. please e-mail me directly if you have a serious answer to this problem.
Also if you have a cb100n wiring diagram / cg125 electric start model wiring diagram, that you can e-mail to me would be great.

Answer 1

First, you have an alternator, not a generator if it is putting out A/C and needs a rectifier. I am not familiar with that particular bike, but generally there will be 3 wires going to the regulator. These in your case appear to be yellow, white, and green. Most systems I have seen have a fourth wire, usually black.

The A/C voltage checks should be from each terminal and ground (or the fourth wire)

Each wire goes to a separate winding which produces one phase of A/C voltage.

The rectifier takes the output from these phases and converts it to DC: a positive and a ground.

I assume this bike has a 12 volt battery: if so the voltage out of the rectifier, or at your battery, should be 14.2 volts DC or so

(7 volts for a 6 volt system)

A/C output between each of the alternator windings and ground (THAT'S GROUND, NOT BETWEEN EACH OTHER!) should be approximately equal, I would think at least 8 to 10 volts A/C

Answer 2

I'm not that familiar with these models as they weren't imported to the United States.
Honda color codes have remained the same since day one and between all models.
The voltage readings you show are very low. From the alternator should read about 50volts AC when the engine is reved.
The rectifier changes it to DC and the regulator sends the excess voltage to ground.
-Either the regulator isn't allowing more voltage to the battery when the lights are turned on.
-Or the AC generator is bad (Honda sometimes calls the alternator, an AC generator).
-Are you using the regulator/rectifier from the cg125? The alternators on each bike is different from one another. If you're using the electrical parts from the cb100 on a cg125 engine, the electrical parts might not be compatible with each engine.
Contact me if you still need diagrams. I don't think they'll be useful. The wiring on Hondas are so simple.

Answer 3

Yeah, Ignore the Harley solution. You don't have time to go back and pick up all the bits that will fall off it.
It would appear you have it wired incorrectly. However, it's not something that can be resolved over the Internet. Lots more information is needed and a visual inspection by a vehicle electrics expert is your best option. Sorry, I know this is going to cost, but that's the down side of owning vehicles.