Charging Issue

Hi all. I'm trying to pin point the problem with my CB500 not charging properly. Through a process of testing and replacing components with known working items, I believe I have eliminated the rectifier,battery, wiring, connectors etc, and everything except the stator coil, I have carried out the resistance tests and continuity tests given by the haynes manual and they are within spec. The haynes manual does not give specs for the AC volts output from the coil. I have measured the output on my bike by connecting a voltmeter across the three yellow wires from the coil in all three combinations and @ 5000 rpm I get around 45volts. I have read on the internet that a reading of 45 - 75 VAC is nornmal for a motorbike. Is anyone able to measure the output on a good working CB500 charging system before I buy a new stator?

From when I was doing this test on my bike (in the past), I would say that 45v AC sounds about right, although it was a while ago, so I may not remember correctly.

What are the symptoms of the charging problem?

Have you tested the regulator/rectifier with your multimeter (to check one of the diodes hasn't blown)?

The symptons are that at 5000rpm with the lights on im getting 12.5V, not enough to charge. But with the lights off i'm getting 13.6V. I have checked the rectifier diodes, as well as trying a known working rectifier. I mentioned that I have eliminated the wiring , but only in so far as between the stator and rectifier. Today I'm going to check for any problems or resistance in the positive and negative paths from the rectifier to the battery using voltage drop testing. A resistance in one of these pathways could explain why when under load with the lights on, the voltage is insufficient. Most likely the positive pathway as it contains the ignition switch. (any switch or moving contact has potential for problems as we know) I'm going to use a testing flow chart I found on the net: here's the link: ooops new members aren't allowed to post links for 7 days Ive been informed, so try searching the below.

electrosport.com/media/pdf/fault-finding-diagram.pdf

A very useful chart. If I can't solve the problem with this then I'm going to give up and become a monk in Tibet!

Thankyou for your reply and I will post back when I have some results.

Welcome Richard!

Just a thought, what voltage are you getting across the battery with the engine idling & the lights off?

Hi ...
Your stator has gone to ground by the sound of it ..
The stator will still put out the correct voltage but won't charge properly . The way to test this is do a continuity test on the three yellows to earth, if any one of the three yellows zero out its knackered ..

Hope this helps

In answer to teamster1975s question . The voltage across the battery at idle with the lights off is 12.4V

In response to kwackboy, there is no continuity between any of the 3 yellow stator coil wires and earth. I understand that continuity here would mean a shorted coil.

I didn't have time to follow the flow chart as below. Will let you all know the results when I have them.
electrosport.com/media/pdf/fault-finding-diagram.pdf

I would like to thank everyone that has replied to this post so far. As a new member its good to know theres people willing to spend a few minutes trying to help others. Many thanks again and I look forward to the time when I can post a problem solved message.

richardmorgan1 wrote:In response to kwackboy, there is no continuity between any of the 3 yellow stator coil wires and earth. I understand that continuity here would mean a shorted coil.

Hi,

Maybe i should have explained a bit better but Basically when you test the continuity between earth and any of the 3 yellow wires your meter shouldnt read a thing, it doesnt have to go to zero. Any movement in the reading means there is a problem. What did your meter do ..?

Hi, meter showed OL when connected to any of the yellow stator wires and earth( or battery -).

Have some results today though. I have some resistance in the positive ignition switched supply. A voltage drop of 0.55V which is too high. Anything below 0.2V is regarded as acceptable. (This may explain the low voltage reading when running with the lights on.) I will try and clean the ignition switch contacts and connections etc and see what the situation is after that.

But regardless of the resistance issue, when measuring the AC voltage output from the stator, I'm only getting 43V from any of the three wire combinations. The flow chart link I posted previously suggests a reading of 50V or more is acceptable. Can't find any data to give me a CB500 stator output figure. But an earlier reply to this topic suggests that this figure maybe normal.

Once I have cured the resistance problem in the switched + wiring, then I will re-test.

Will let you know, but maybe a week before i can post an update.

Just to re-cap, all the haynes manual tests for stator and rectifier have been acceptable and within limits/specs.

What tests did you do on your battery and how old is it....? have you done a load test..? Did you know that depending on how good your battery is determinds how much voltage it takes to charge..? so for example if your battery is getting on a bit it maybe fine without lights but once its under load it might struggle to take in volts.......

Battery is about 1 year old. It charges fine with an optimate smart charger and holds it charge at around 12.5V. I assumed battery was good.

However, It may be worth doing a load test anyway just to rule it out for sure.

Good point..... Many thanks

There were a few corroded connections in the wiring loom which have been cleaned up, as well as the ignition switch contacts.

Now at 5000 rpm with the lights on I'm now getting 14.0V which means battery is being charged.

However, at idle with lights on, I,m only getting 11.7V. (Battery being drained)

I believe the stator is weak but won't replace it yet. Unless I spend more time in traffic idling than I do on the move, I don't have any issues. Will post again if I need to replace stator.

richardmorgan1 wrote:

However, at idle with lights on, I,m only getting 11.7V. (Battery being drained)

.

Turn your idle up a bit .. because i spend so much time in traffic i set my idle to about 1400 ... charging never goes below 13.8v ..

i had the same problem and i fitted a new rectifier and that cured the problem .



this is what i bought http://www.ebay.co.uk/itm/UK-SELLER-New-Rectifier-Honda-CB500-S-93-04-/190647736236?pt=UK_Motorcycle_Parts&hash=item2c637d97ac