CG125 duff rectifier/ regulator?

[mudcow007]

Evenin' all

my little cg is popping bulbs as much as the average scally wag pops tablets in a club on friday night.....

anyone know what voltages i should be getting coming out of the rectifier with the engine running?

with the bike idling i get around 10v at the yellow wire (straight from the genny - i dont know if this is normal)

i couldn't rev the bike as i was holding probes onto cables..but im guessing the voltages would/ should have increased with more rpms

i will check the white wire too.

my guess is that the rec has failed an is not taking off the excess voltage from the genny.

i will check the voltage at the blue & white (headlight) tomorrow

sorry for the long message

[Paddy Blake]

It it the 6v or 12v CG.

With the old 6v CG I used to put in a 12v bulb in the headlight to stop it from blowing.

[mudcow007]

12v mate

im thinking about scrapping the headlight an sticking a torch on the front, would probably be more brighter

[Howling TerrorOutOfOffice]

My first thought would be too much vibration causing the bulb failures, especially if it's always the same light that blows.

However, you can see if the reg/rec is working by hooking up the multimeter to the battery and see if it shows 14-15v with the lights on and revved to about 5k. Any more or less then it's time to check the output from the stator.
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The Harry Turner Project

[MatteyA]

As above, start her up, hold it at 5k revs and expect to see 14-15v accross the battery terminals, that will tell you if the charging system is working properly.
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CBF 125

[Cyclingbiker]

As above I'd check the voltage across the battery terminals with the bike running, just wedge the probes into the terminal between the metal and the plastic/rubber sheath to hold them in place and measure with the meter set to DC.

Should get around 13.5v at idle rising to around 14.5v maximum with about 1/2 throttle. That should let you know if the charging system is doing its job properly. When I accidentally disconnected my reg/rec the symptom was that I was popping bulbs like no tomorrow and there was no increase in voltage across the terminals, it just stayed a steady 12v.

If you get no voltage increase then you know the reg/rec or the wiring in between is the issue

Oh yeah and 10v is way too much from the yellow wire at idle, should be more like 6-8v and would rise slowly to 12-15v with more revs. Definitely sounds like something to do with the rectifier or the white wire to me going by experience.
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Honda CB500s (1999) - Honda CG 125 BR-J (1991)

Mod 1 - Passed - 12/11/12 --- Mod 2 - Passed - 26/11/12

[mudcow007]

cheers all, i tried to test everything last night an the bastard wouldn't start..

i have ordered a spankingly new rectifier/ regulator anyways (only £20 off gaybay) as god knows how old the one i have is anyways....

fingers crossed i get the thing working soon

have a pocket full of

[mudcow007]

**update**

got a multimeter on my bike tonight

at idle with no lights on at the battery its 13.6v

reving high it hovers around 14v

i didnt measure with the lights on, will check that tomorrow..

one thing i noticed i changed the right had switch gear as the original had broken wires an full of crud inside on the contacts

the new one has spare wires...

yellow with white trace
red with white trace
pink

the pink i think someone on here mentioned that on some models it went to a resistor

god knows what the other wires are for they dont show up on my diagram...?!

[odgeuk]

Was it the Voltage regulator?

I've got a 1989 CG125 BR/J which blew the main headlight almost immediately after putting a new battery in. Not long after I dropped the bike and had to replace the whole Headlamp, which came with new bulbs fitted, and in no time at all Main headlight blew again.

Don't want to fork out £20 on a regulator just yet, nor do I want to go through another bunch of bulbs. Can I prove it to the regulator using a multimeter first?

At the moment, I've just got one working bulb, which only comes on when I switch to full beam. It's a bit bright to just use that at night!
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Honda 1989 CG125 BRJ
Honda 1989 CBR600F-K (Requires a MOD2 Certificate before I can ride it!)

[Mark65]