CBR 125 Charging fault

Old 12-01-2013, 05:58 PM
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Unhappy CBR 125 Charging fault

Hi guys, I'm hoping that you'll be able to share your knowledge and help solve my issue with my 2004 CBR 125.

I recently bought the bike and it ran fine for the first week, then one morning it wouldn't start, starter motor turned but the bike wouldn't kick in and after several attempts the starter motor gave up as well as the neutral light dimming out.

I took the battery out and stuck it on a mutli meter and it was completely flat, whilst the battery charged i stripped out the third party alarm just incase this was the issue and left the battery to charge over night.

I then decided to purchase a new battery as the old one had seen better days hoping this would solve my issue, with the new battery in i decided to run some test, standing the volt read at 12.9v with the bike just started and idling quite low (cold weather, 1000-1200rpm) the voltage dropped and fluctuated around 12.3-12.6v, once the bike had warmed and idles around 1600-1800rpm the voltage read around 13.3-13.6v which i thought seemed ok.

This is where i noticed the issue, when i rev the engine the voltage started to decrease... the higher the rev the lower the voltage, the lowest it seemed to drop was 12.3v which explains why the battery is now dying again after a month of light use.

Am a right in thinking that i have a faulty Stator? i've done some research and a lot seems to point to the regulator but i thought the regulator was there to control the voltage i.e reduce it if the stator is pumping out to much. If the voltage is never going above 14v is it more likely to be the stator not producing the output?

Any insight would be much appreciated!!

Thanks guys!
Old 12-03-2013, 07:22 AM
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before you purchase anything follow through this fault finding guide, it should help you decide which part is at fault,
Old 12-03-2013, 01:02 PM
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Hi Wheelnut,

Thanks for the link, I performed section C of the guide I believe correctly lol, I did the first test: connect the red meter lead to the red output of the regulator and black meter lead to the yellow wire connector points one at a time and the meter displayed no change in voltage or ohms, I decided to do the second part and connect the black meter lead to the regulator red output and the red meter lead to the yellows one at a time and got a reading this time ranging from 1.17 on one of the yellows up to 1.24 on another.

As I didn't get any readings with the first section am I safe in safe in saying the regulator is dead?
Old 12-03-2013, 02:21 PM
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I'd hazard a guess that your r/r is toast. Not uncommon on hondas.
Old 12-04-2013, 05:36 AM
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Ok so this morning i done a few test.

I tested the stator disconnected and got 0.6ohms across all 3 yellow cables which seemed ok.

I then decided to test the AC current whist idle and got 11.6v across all 3, then i tested all 3 at 5000rpm, heres the results:

1st pair: 4.5v 2nd pair: 2.6 3rd pair: 10.6v

Safe to say the stators dead?

Also i tested the positive and negative lines from the battery to the R/R, Positive came back at 0.36v which from what i've read is high and means theres an issue some where along the positive line.
The negative came back at 0.02v whice i believe is ok?
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