Help! Really dim headlight and tail light on CG125E

[Dadams9876]

Hello.
First time posting. I recently bought a 1981 cg125E, it runs pretty well (as long as I keep cleaning the air filter, carb and spark plug).

It had been sitting for about 8 months but had had the battery replaced.

The problem I have is the head light (and full beam separate bulb) and tail light are so dim they are barely visible. They do get a bit brighter when I rev the engine but not by much.

The brake light and indicators are nice and bright, although the indictors have stopped flashing and are solid on.

I'm really not sure what I am doing and was hoping I could get some advice as I have very little money.
As far as I can tell it is a problem with the alternator/stator/flywheel. However I can't find any replacement parts for this model online (I can't even remove the stator plate as the screw heads are warn).

My next thought is to buy new bulbs, and clean all the electrical wire connections. Other than that I don't know what to do. Oh its a 6v bike if that helps

Any help would be greatly appreciated.

Kind regards

David

[jaffa90]

You really need a multimeter to find the fault, sounds like the battery is not charging now you say the indicators don`t flash.
It could be the battery, reg/rec, generator or their connections.

[Dadams9876]

That's great, thanks.
I have just ordered a multimeter online. So I will check all the cables, lights, battery, generator readings etc against what its says in my Haynes manual which will hopefully identify the fault.

If it does show what I suspect to be the generator that is not charging the battery or powering the lights, how do I tell if it is the stator coil or the magnet that needs replacing.

I have found somewhere (west country windings) who can restore the coils on the stator plate (if i can get it off) but still can't find a replacement magneto flywheel in case its that.

[jaffa90]

The coils have resistance values (ohms).
The wires from the generator to the reg/rec are A.C. and from the reg/rec to the battery are D.C.
One A.C.wire should go to the ignition switch and then the ignition coil for the spark.

[smallfrowne]

Forgive me, stupid question, but are all the bulbs def 6v ones and not 12v? Also are the bulbs in the clock the right ones? ie 6v and low wattage ~3W? I've seen you can get 30W clock bulbs, which would make your speedo glow nicely but would sap the juice from elsewhere - and there really is no extra capacity from the little stator.

There is no reg/reg on it, just a diode that stops one side of the AC from getting to the battery, making it DC. But the battery only runs the horn and brake light, oh and the (daytime) indicators, lights are all AC.

When you get the multimeter don't forget to check running voltage - with a few revs on. Haynes is deffo your friend. Check it with lights on, lights off. Also try disconnecting the resistor that lives under the headlight bowl on the fork bottom if the voltage is really low, maybe that is somehow sapping power. Maybe.

It could well be the stator. I doubt it'd be the flywheel as that is just a bunch of magnets BUT I do have a spare one I could part with. If it's knackered you should be able to tell because the magnets will break apart/have signs of breakage - I think that's the only way it can actually be knackered. They are very brittle and once they start to break up they've had it. Come to think of it, you probably can't tell without removing the plates that hold the magnets on - DON'T DO THIS I TELLS YE!! Unless it really is the last thing you can possibly check, and I'll sell you a flywheel for £50 (you can mop up the tears with said fifty note before you give it me if you want, I won't mind).

Good luck, multimeter will be your best pal now.

PS I have a nice wiring diagram on another thread... lemme know if you need it.
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'90 VFR750; '89 NC30; '95 DR650; '89 CD250U; ~'82 CG125; ~C90

[Petemate]

Very good post smallfrowne - our scholar should be able to sort his problem with the excellent info.
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82 not out....1983 Honda LA250 Custom
2008 Saab 9-3 1.9 Tid 150 Vector Sport estate
2005 Stirling Eccles Topaz 2-berth

[neptune8]

It is unlikely to be the flywheel/ magnets that are faulty. Get hold of a Haines manual for your bike, which will include a wiring diagram, and details of how to test the stator with a multimeter. Test stator before removing or renewing it. As suggested, your bike likely has a 6 volt system, and 12 volt bulbs will not work. Test battery voltage with engine not running. Should be at least 6.4 volts. with engine running at about 5,000 rpm, voltage should rise to around 7 volts. No voltage rise equals, no charge. Not charging could be caused by faulty stator, flywheel, rectifier, wiring or rectifier. Rectifier on 6 volt CG125 is a simple two terminal job, easily tested with a multimeter. If battey voltage is low, recharge it using a proper motorcycle 6 volt charger, not a car battery charger. Haines manual may be available online.
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Enjoy yourself, its later than you think

[smallfrowne]

Oh and one more thing, afooer I forget, check that the wiring to the rear lamp cluster is plugged in correctly. There are 3 wires, ground, brake light and rear lamp. On mine the rear lamp and brake light were switched meaning that the brake light was on with the headlight and the brake switches activated the tail lamp.

The tail lamp is 5W but the brake light probably 25W - it made a big difference when I corrected that one. Stator couldn't handle 35W headlight, 3W clock + 25W rear light. (numbers may not be fully accurate).

Still, if it's not charging with the lights off, it's probably something else, but I thought I'd mention it.
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'90 VFR750; '89 NC30; '95 DR650; '89 CD250U; ~'82 CG125; ~C90

[jaffa90]

Image result for honda cg125E wiring diagram,
[img][/img]Image result for honda cg125E wiring diagram
[url]

[Tamsin]

I know next to nothing about the 6v bikes... but on the later ones it's only the headlight and tail light that are run directly from the Genny. We're the lights running nicely before the bike was stood do you know?

Fwiw, the lights on CGs are crap at the best of times...

[smallfrowne]

Here's the diagram I use. Sorry it's not all coloured in, I was only interested in half the diagram at the time (a 6v points to 12v cdi conversion).

https://imgur.com/igNs4Pal.jpg
Click for big.

It's same as above really but quite clear I think.
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'90 VFR750; '89 NC30; '95 DR650; '89 CD250U; ~'82 CG125; ~C90

[chris-red]

6v electrics are shit, charge/replace the battery and invest in some halogen bulbs is about all you can do.

You could go through the loom ensuring every connection is clean and makes good contact too.

With my RXS the indicators would only flash if the engine was reving or the lights off.

I got mine from here.

https://www.norbsa02.freeuk.com/goffybulbs.htm
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Well, you know what they say. If you want to save the world, you have to push a few old ladies down the stairs.
Skudd:- Perhaps she just thinks you are a window licker and is being nice just in case she becomes another Jill Dando.
WANTED:- Fujinon (Fuji) M42 (Screw on) lenses, let me know if you have anything.

[jaffa90]

[smallfrowne]

Yeah, sorry, it does have a rectifier, but that's just a single diode it is an old cg diagram i think it lacks the resister that is in series with the pilot bulb but otherwise it's the one. (i have a cgE and it mostly matched this diagram)

Hmm also I have some unused, untouched 6v halogen bulbs going spare actually. Infact i have a spare rectifier diode too if anyone needs one..
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'90 VFR750; '89 NC30; '95 DR650; '89 CD250U; ~'82 CG125; ~C90

[Commuter_Tim]

Too drunk to read the helpful peoples replies, but I did have the same experience as you OP.
Can't help with the electrical fault, but even if you fix it, the headlight will still be pissweak.
The headlight being dependant on revs isn't likely to go away entirely either.
My 1998 12v CG had dangerously underpowered headlights.

I just chucked a KREE lamp on the handlebars.
https://www.themarysue.com/wp-content/uploads/2014/02/Kree-Military-Uniforms-2.jpg https://i.ebayimg.com/00/s/NTAwWDUwMA==/z/h04AAOxy4dNS-pYv/$_3.JPG?set_id=2

Routed the cable to a battery pack I velcro on and off to the sissy bars.
Job Jobbed, you can blind anyone you like and light up the road to eternity.
You can also literally melt the skin off your fingertip if you touch the lamp after a long ride.
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The above post is most likely nonsensical.

I ride a Bandit 600... badly.