honda cg125 1982 batteryless?

[danwilde]

Hi all!
I'm currently building a custom honda cg125 and really want to run it without a battery but still have a headlight, ive heard from many people you can but there are no details e.g what wire goes to what? im an absolute novice at wireing but with some good instructions im sure ill be ok, im pretty sure its points and its definitly a 6v system. All the wireing have been removed by the previous owner so all i am left with is black,red,yellow and white wires comeing from the magneto.

Any help would be much appreciated! Cheers!

[mudcow007]

Sure its 6v?

My 1982 was 12v - my engine was a "BR" check by the gear selector, engine code will be stamped into there

6v headlight would be gash aswell...I think the light on my cheap casio watch is brighter

[danwilde]

Thanks for the reply! It sais its a cg125E and asked the previous owner and he said it had a 6v battery on it from his memory.

[smallfrowne]

I have an 'E' - it was 6V. It probably can be done. The battery provided juice for the indicators and brake light, the horn too I think.

Wiring diagram (click for bigger)..
https://i.imgur.com/igNs4Pal.jpg

The yellow wire from the stator goes to the handlebar switch, which switches it either to the blue (high beam) or white (low beam).
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'90 VFR750; '89 NC30; '95 DR650; '89 CD250U; ~'82 CG125; ~C90

[danwilde]

Brilliant thanks!
Im still trying to make sense of this, im going to run a headlight but do not need to go high beam or low, just want to keep it on low, so i do not need to the yellow wire? Same with the pink and white?

I only need to get a spark to I run the black wire to my key ignition which then goes off to my horn and my coil seperatly? Sorry if im being dumb but im new to all this wireing mumbo jumbo business, also i need a rectifer to covert the AC - DC? and that must surely go after the magneto right at the start? If anyone could put some links up for the right rectifer that would be a huge help! i do not have a block connector comeing from my engine it is litterally just those wires i have mentioned, i would safely say somebody had butchered it before.

Cheers, much thanks!

[smallfrowne]

In that case, the headlight has two wires, connect one to the yellow wire and the other to ground. You don't need a rectifier, i think it's regulated by the fact there's a bulb there drawing current - but that's with a 2 lamps and a battery connected. The pink and white you can just leave alone.

I'd get the engine going and test this out first before you wire up a loom - get a multimeter and see what the ac voltage is like from yellow to ground, see if it's anything like 6v, cause if it's much higher the bulb won't last very long. Then try out with a bulb and test the voltage again - don't forget to increase the revs!
____________________
'90 VFR750; '89 NC30; '95 DR650; '89 CD250U; ~'82 CG125; ~C90

[smallfrowne]

The spark comes from the black/white wire, it goes to the ignition coil and condenser. It continues to the ignition switch, where in the off position it grounds the black/white wire (goes to green) - which causes the 'spark' to never reach the ignition coil or spark plug, thus immobilising the bike. Which is pretty shit as it makes it very easy to bypass if you don't have a key.

Are you wanting a horn as well?

Also, pictures of the custom cg please
____________________
'90 VFR750; '89 NC30; '95 DR650; '89 CD250U; ~'82 CG125; ~C90

[smallfrowne]

M-m-m-m-multipost....

Just to be clear, the lamp will run off AC so doesn't need to be rectified (AC-DC).

I'm unsure if it will need regulating (kept at ~6v), I'd just try it first.
____________________
'90 VFR750; '89 NC30; '95 DR650; '89 CD250U; ~'82 CG125; ~C90

[mudcow007]

Dont older CG's have a big ol resistor stuck on the headstock to smoothen out the volts?

[smallfrowne]

You're right, the resistor is only used when the pilot light is selected though iirc. It might be an idea to use the resistor in-line with the lamp if the new set-up keeps blowing bulbs due to excessively high voltage though.
____________________
'90 VFR750; '89 NC30; '95 DR650; '89 CD250U; ~'82 CG125; ~C90

[danwilde]

Thanks for all the advice and ill try and put some pics up in the next couple of days smallfrowne of my bike so far when i have access to a phone with a better camera than my calculator
Cheers!

[redeem ouzzer]

How would sir plan on passing an MOT with this contraption?
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Be a REAL MAN!

[danwilde]

Just putting it through a day M.O.T and then hooking up the headlight afterwards.........hopefully

[Monkeywrenche...]

[danwilde]

Just prefer the bike to be all stripped back but not keen on the look with no headlight.