Topic: testing oem regulator and rectifier

[kawabunga]

That volt drop is too high work from battery along loom with black probe. First turn kill switch off and disconnect headlight and tail light
Start at battery lead on solenoid
Input of fuse
Output of fuse
Ignition switch red
Turn ign on
Ignition switch black
Multi black in headlamp.

Somewhere you will find that volt drop and the problem is between that point and previous test point.

Come back with results/questions.

Results:

Headlight, taillight and front running lights unplugged (fuses left in place).
Killswitch set to off.

12.7v Battery terminals
12.7v Start at battery lead on solenoid
12.7v Input of fuse
12.7v Output of fuse
12.7v Ignition switch red
Turn ign on
12.3v Ignition switch black
(Battery settles at 12.4v with ignition on)
12.2v Multi black in headlamp. (See note below)

Not entirely sure what you mean by multi black in headlamp. I found one black wire with a double female plug coming from the main harness into the headlight bucket. Only one male plug is connected to it and it goes to the group of wires that run to the indicator lights above the key. All the other black wires in the bucket are turn signal related.

Measurements at the black and white terminals of the regulator:

Lights unplugged, killswitch off 12.2v
Lights unplugged, killswitch on 11.2v
Lights plugged in, killswitch off 11.1v
Lights plugged in, killswitch on 10.4v

Again, all of these readings are engine not running, no stator installed, field coil unplugged and battery left off tender for the night prior.

What can I test next?
What can I do to increase voltage at the regulator?

The stator is on its way back from Rick’s so I’ll be able to test with that hooked up and running soon.

[bryanj]

First thing i notice is you are loosing approx 1/2 volt across ignition switch which is not good. They can be taken apart and cleaned/re greased.
Second thing is battery voltage is dropping quite a bit with load on it which makes me think battery is getting tired.
Third is that the difference between ignition switch black and reg black makes me suspect a poor contact sowhere inside the loom.

Pesonally to test i would put everything together leaving the black off the reg and then when engine running use a jumper lead from battery positive to the connector on reg box that the black goes to and see what your charging does, not forgeting it wont charge till higher revs.

If that gives you a better charge rate i would splice a new external black lead between the black at ignition switch block on loom and regulator whilst looking for a better loom.

[Erny]

I had similar issue on BLK line (high voltage drop), finally I found issue on corroded junction inside wiring loom : http://forums.sohc4.net/index.php/topic,176018.msg2048272.html#msg2048272
Just 2 weeks ago, when I was doing bike yearly inspection, I found that sleeve again full of water (probably from last autumn washing)!...so no surprise there were corroded junctions after 40 years

Back to you - do what bryanj suggested:
1. clean IGN switch
2.  test with jumper lead to regulator blk terminal and if better then run new external blk wire to regulator

Note: I personally installed relay to offload IGN switch and ensure good contact/low voltage drop. Maybe cleaning switch would help too, but I did not know it can be cleaned time I was doing it

[kawabunga]

I had similar issue on BLK line (high voltage drop), finally I found issue on corroded junction inside wiring loom : http://forums.sohc4.net/index.php/topic,176018.msg2048272.html#msg2048272
Just 2 weeks ago, when I was doing bike yearly inspection, I found that sleeve again full of water (probably from last autumn washing)!...so no surprise there were corroded junctions after 40 years

Back to you - do what bryanj suggested:
1. clean IGN switch
2.  test with jumper lead to regulator blk terminal and if better then run new external blk wire to regulator

Thanks for the suggestion, Erny!
I stripped back the wire harness cover to where it branches by the coils. The junction of all the black wires looks great. It measured 0 ohms resistance and the voltage was the same before, at, and after the junction.
The original tape was starting to fall apart and I wanted to rewrap it anyway.

First thing i notice is you are loosing approx 1/2 volt across ignition switch which is not good. They can be taken apart and cleaned/re greased.
Second thing is battery voltage is dropping quite a bit with load on it which makes me think battery is getting tired.
Third is that the difference between ignition switch black and reg black makes me suspect a poor contact sowhere inside the loom.

Pesonally to test i would put everything together leaving the black off the reg and then when engine running use a jumper lead from battery positive to the connector on reg box that the black goes to and see what your charging does, not forgeting it wont charge till higher revs.

If that gives you a better charge rate i would splice a new external black lead between the black at ignition switch block on loom and regulator whilst looking for a better loom.

Bryan, I should have noted that when I measured 12.7v on the red wire at the ignition, the ignition was off, and when I measured 12.3v on the black wire at the ignition, the ignition was on.

I let the bike sit on a trickle charger last night since I was messing with it so much yesterday, but I went and retested the red and black wire at the ignition, and they measured the same tonight at 12.5v with the ignition switched on.

In post #16 I mentioned that I already dissembled and cleaned the ignition switch. Here are the before and after photos. I did not disassemble the switch any further than this, so if there's more to clean, please let me know. I also disassembled and clean the killswitch itself. It wasn't as bad as the ignition switch, but it was dirty. If I recall correctly, cleaning both of these gained just under half a volt. I think...



Also, here's the melted main fuse. You can see it's drooping a bit compared to the other fuses.



Tonight, with the bike switched to on for at least 30 seconds, killswitch set to off, and all the lights but the tach gauge light bulb unplugged, the measurements are:
12.6v Battery terminals
12.6v Start at battery lead on solenoid
12.57v Input of fuse
12.53v Output of fuse
12.48v Ignition switch red
12.48v Ignition switch black
12.44v Black and white terminals of the regulator

I really seem to get the biggest drop when the killswitch is switched to run and/or when the lights are plugged in.

It's flippin' cold in the garage tonight, so later this week I want to experiment with switching the lighting to LED since I have some LED lights I can easily steal from another bike and do some quick testing. I'll switch all the lights over and compare what I get for measurements and report back.

Is it possible to run the Dyna S electronic ignition with a set of OEM coils without issue? I still have my original coils. A while back, when I was chasing other problems, I thought they might be going bad but perhaps they're fine to use and maybe that will gain me some voltage. Hate to have money invested in parts that aren't being used though...

Anything else I can try while I wait for the stator to arrive?

P.s. - Thank you for all the help. I really appreciate you taking the time to help me get this sorted.

[bryanj]

No first hand experience of Dyna but i believe it will work with standard coild.
Never liked the US idea of lights instantly on, drains the battery too much on a marginal system.
Here in UK they tell us to turn them on but at least we can start it and let it try and put a bit back in before using a switch.

[kawabunga]

Well, I think I may finally be in the clear!

Got the stator back but I did some testing before plugging it in.

I measured all the yellow wires, .7, .7, .6. According to my Haynes manual, they're all too high of resistance (.2 I think it states...), but the individual I spoke with at Rick's Motorsports told me that when they rewind stators for these CB's they typically go out the door between .5-.7 ohm. He said he wouldn't hesitate running my stator.

I checked the OEM coils and the new Magna coils currently on the bike. Interestingly, they measured nearly the same.

Then I tested incandescent vs LED lighting draw.
Stator/field coil unplugged, killswitch OFF.
At the black terminal of the regulator:
11.48v Incandescent
11.91v LED
.43v gained, not bad.
I swapped the headlight, front turn signals w/running lights and brake/taillight. (The lights that come on when the key is turned minus the dummy and gauge lights.)

Then, with the LED lights installed, I hooked up the original coils to compare to the high-output coils.
Stator/field coil unplugged, killswitch ON, LED lighting.
At the black terminal of the regulator:
11.06v Magna coils
11.11v OEM coils
That surprised me. Only .05v gained. Not enough to get me to put the OEM coils with 45 year old, hardened plug wires. I will keep them on hand incase a need for them arrises.

The final step, get the bike running! Again, I tested with incandescent vs LED lighting at various engine speeds. I will preface that my tachometer is not the most accurate, but it's in the ballpark. Measurements are also averages since they hop around slightly, but I held the throttle steady to get the voltage to level out and hold.

With incandescent lights, voltage at the battery terminals:
12.0v @ Idle
12.7v @~ 3,000 RPM
13.0v @ ~ 4,000 RPM
13.4v @ ~ 5,000 RPM
13.2v @ ~ 6,000 RPM

With LED lights, voltage at the battery terminals:
12.2v @ Idle
13.0v @~ 3,000 RPM
13.7v @ ~ 4,000 RPM
14.0v @ ~ 5,000 RPM
13.2v @ ~ 6,000 RPM

With LED lights, that sounds adequate to me. I could probably even manage to get away with standard bulbs but those voltages are lower than I would like to see. I'll be swapping everything over to LED and see what it's like to live with for a while. I plan to keep the new coils and Dyna S ignition installed. If I continue to have issues the coils will be the next thing I swap back. Hope it doesn't come to that though. Fingers crossed that she keeps a charge!

I am curious though, why does the voltage start to drop after the revs go past 5k RPM?

Again, thank you so much for helping me get this sorted! I really appreciate it.

[bryanj]

You are the second person that has reported a drop off in voltage and i dont have an explanation for it.

Just like i dont have an explanation for my 5yr old "smart" battery charger that has only been used 5 times deciding to crap out, or the genuine Mitsubishi accessory wiring kit with a relay wired wrong so it discharged the battery.

You apear to have sorted it enough to run and now understand electrics a bit better.
Big problem nowadays is the multitude of cheap digital multimeters about, yes i have them as well, that are just not accurate at low readings. All the old names like Avo, Fluke, Megger etc are just too expensive for home use sitting arround doing nothing for 95% of the time.

All the best and keep well

Bryan