CG125 - runs great but no electrics (apart from headlight)!

[wulfprints15]

Hi all,

As title states. I've got a (heavily modified) Honda CG125 (1996 - I believe a BR-ST or BR-K model) which, mechanically, runs very well but, electrically, is basically completely broken.

I've got no indicators, no horn, no neutral light. All I've got is the headlight. The rear light seems to light up dimly but does not light up when braking.

I think this could have something to do with the ignition switch. It rotates quite freely in its housing. It used to be that I could fiddle with the positioning a bit to get a good connection and then all my electrics would work, but this doesn't work anymore.

I've taken the seat and tank off to get a closer look at everything but I'm not sure how to get at the ignition switch. I'm guessing it's designed not to be easily tampered with for obvious reasons but I want to get in there and check the wires.

Any ideas on where to start troubleshooting? So far my best idea is to just systematically check each wiring connector but this could take yonks!

Cheers,

Jamie

[wulfprints15]

While I'm here. Quick other question: I've seen that most recommend 10W40 for CG125s. I've got 3 ltrs or so of good 5W30 motorcycle oil. Would this do the trick rather than purchasing new oil?

[Riejufixing]

New switches are surprisingly cheap! This might help:

https://die-kleinkraftrad-ig.de/wissensdatenbank/reparaturanleitungcg125.pdf

16 Ignition switch: location and replacement

1 On early models the ignition switch is secured to a bracketrubber-mounted to the frame top tube, underneath the frontleft-hand side of the petrol tank. If the switch is to be renewedthe tank must be removed so that the switch wires can bedisconnected; unscrew the plated retaining ring to release theswitch from its bracket. On refitting, use a hammer and a smallpunch to tighten the ring without marking it.

2 On CG125-C and E models the switch is mounted in thewarning lamp cluster, next to the speedometer. Remove theheadlamp rim and reflector unit (see Section 6), then trace anddisconnect the switch wires. Remove the headlamp shellmounting bolts and allow the shell to hang down on the wiring.Remove the two screws which secure the cluster housing to itsbracket, unplug the warning lamps and withdraw the housing.Use an electrical screwdriver or similar to disengage the clipswhich secure the switch to the housing. On refitting align theswitch with the housing and press it into position from aboveuntil the clips snap into place.

(if it's your model)

[Riejufixing]

[stinkwheel]

Switches are anti-tamper. The switch is attached to the top yoke. You need to remove the top yoke complete with the switch then find a way of removing the anti-tamper bolts. The bolts come with a head attached to the rest of the bolt with a thiun "neck" which they tighten until it snaps off, leaving a domed head with nothing to put a spanner on. It's to stop theives simply unbolting the lock. Almost totally impossible to remove them with the top yoke on the bike.

If you are very lucky, you'll be able to put the top yoke in a vice and tap them round with a punch, or dremmel a slot in them and use a screwdriver. Otherwise it's a case of welding a nut to them or drilling the head off.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[wulfprints15]

Cheers guys, I'll take a look tomorrow. Hope it's not too much of a pain!

[stinkwheel]

Should be able to get aty the actual wiring coming from the switch in the back of the headlight.

Just a thought but if you're not sure about testing it (and it's not the kind of thing one ought to put up on a public forum as it's effectivelty a guide to hotwiring a bike) but are pretty convinced the switch is dodgy, you could connect the replacement and test it before taking the old one off.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[wulfprints15]

[Stalk]

With respect, a heavily modified 96 125 is going to have enough to put people off, so a non genuine switch is not going to make a difference.

[stinkwheel]

I'd expect a '96 CG125 to have been stolen at least three times in its lifetime.

It's probably why the iginition switch is ropy in the first place. Having a screwdriver hammered into them tends to do that.

You can most likely re-key the fuel tank lock so it matches the new ignition key by re-arranging the keepers in the lock itself. Plenty of how-tos out there.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[wulfprints15]

[1198]

If you've got the top yoke off you may be able to get a set of mole grips on the domed heads - I did at least!

[wulfprints15]

It's actually a model with the ignition on the right-hand or 'off-side' of the bike so there's no yoke in the way at all. I just can't figure out how to unscrew the thing to get it out.

There's a kind of punch-hole. Maybe this is supposed to be used to unscrew it with a punch and hammer?

[Riejufixing]

[wulfprints15]

[wulfprints15]

I've managed to successfully remove the ignition switch or, rather, I bashed the **** out of it until it finally came off.

Upon looking inside the ignition I could see that the contacts for the red wire (which goes to the positive battery terminal) were all green and rusted and not making a good contact anymore at all. If I really pressed it all together I could effectively hot-wire the bike and, lo and behold, all the electrics worked perfectly.

This was clearly the problem then and I've ordered a new ignition switch.

Cheers guys

[2wheelLover51]

I remember having to do this on my daughters low mileage YBR125 and it was a right pain. I removed the top yoke and then ground the rounded ends of the pins with an angle grinder, then used a punch to remove the bolts. Bit of a job though! Seems like the ignition switch is the weak point on both of these bikes.
____________________
2WHEElLover1951

[wulfprints15]

Mine actually came out very easily once I stopped trying to do it neatly. I agree with you though. They must be weak points.

That being said, I don't know how old my ignition switch was and, given its position on the bike, it had absolutely no protection from the elements. Can't exactly blame it for failing I guess!

No wonder they don't put switches down on the sides of bikes much (if at all) anymore.

[steve the grease]

The CG125 has effectively 3 eletrical systems.
1. CDI for the ignition
2 AC lighting for the head/ tail light
3. DC charging system with a small alternator winding , rectifier , regulator and a battery.
Sounds like the last system isn't working. if it's anything like my hondas of old , if you run it without a battery for ages the insulation in the alternator coil breaks down and stops working. Is there a battery?
____________________
All the above is my personal opinion, you can see my lips move, but I'm talking out of my arse.
I've been riding, and fixing , bikes for 50 years, in that time the more I learn, the less I am absolutely sure of.....

[wulfprints15]

Hi, yes, it's got a battery. It's a new battery and I test the voltage regularly which always seems to be fine.

[wulfprints15]

New ignition test fitted and works perfectly apart from a slightly dodgy connection on an old electrical connector. Tools to fix this in the post.

Lucky I'm in isolation and without any time-constraints!

[Easy-X]