First start since 1989 tomorrow!

[Membername]

Thanks Chuck, can I use this to troubleshoot it? 

https://cdn.shopify.com/s/files/1/1091/5694/files/fault-finding-diagram.pdf?235929069374954073

I guess not since it says it only works if there is a combined regulator/rectifier. 

Karen

[paul1478]

PM then call him. He knows what he speaks of and always willing to help. On my RD from the late 70s I had a charging issue and for me it was such a hassle and never figured it out. Wish I had a form like this back then, it would have been fixed I am sure.

[Membername]

Tonight I checked the rotor. I took the brushes out and tested between the two rings, it was 5.7.    Then I tested each to ground, there was not continuity.  I think this means the rotor should be ok?  The brushes were short, but not past the line.  I have a pic below.

Then I tested the rectifier as described in the service manual.  The D1-D3 elements were discontinuous in both directions, and the D4-D6 elements were continuous in both directions.  I think this means the rectifier is not good. 

Is there something else I should check, or just replace the rectifier?  Any suggestions on a replacement?

Thanks,
Karen

[SUPERTUNE]

K,
You have to check the rectifier 12 different ways!
6 checks on each of the red and black and swapped polarity 3 on each.
I don't get the impression your checking it right,
Also check the 3 whites for the stator. You can do it at the rectifier plug, I do both, at the first stator plug and then at the rectifier plug.
Chuck

[Membername]

I checked the rectifier actually 24 ways.   ;D. I checked it for continuity like the manual says (switching the leads for each set of three).  Then since I have a diode tester on my DMM, I tested each of the 12 combinations with that.  The top right wire (looking at the fuse panel) seemed fine with the diode test, each group of three was OF one way and 0.4 when I swapped the leads.  The bottom left wire however read 0.00 in all six combinations, this is why I think the rectifier is shorted.

For the three white wires, what test should I do?  Am I just looking for 12 or so volts on each white wire coming from the rotor?  Do I put one lead on a white wire and one on the cases to ground it? 

Thanks for your help, I don't know a lot about this charging system.  I went to a vintage bike rally on Monday and there was not a single RD.  I really need to rectify that.   8)

K

[SUPERTUNE]

K,
How did you do the rectifier 24 ways?
Forget these fancy meters that most were not around when RD were produced, just not needed.
I get teased with my old meter, all I got to say is vintage bike, use vintage tools!
Just a resistance test between all the whites (3 of them) and to ground to make sure not shorted to ground.
.5 ohm is the spec white to white on all three and 0 to ground on all three.
5.5 ohms on the field rotor is fine by the way.
Chuck

[Frank B]

I don't mean to make more work for you, but also check the stator windings for any point we're the insulation may have been worn off from the windings touching the case and grounding out. That's if you don't find a problem elsewhere.
I recommend the PowerDynamo/Vape system if you end up having to spend a few hundred to replace a few pieces, might as well do it all at once and have no worries.

[Membername]

Chuck,
I will test the white wires as you suggest.

Frank,
I haven't taken the stator off yet, but I guess I need to get a look at the windings like you say.  Is it just those three screws that need to be removed to access the rotor?

K

[m in sc]

if the check ont he s white wores are ok, and the slip rings check out (take brushes out for this check) then you should be ok. dont need to remove that stuff from the bike.

[Membername]

Got it.  So if that all checks out, then it is the rectifier, which tested bad.  I will check it out this weekend. 

K

[Frank B]

Yeah, do the other tests first. Only reason I took my stator out was because it tested bad and I was getting the bike ready for a new one and found the problem on it.

[SUPERTUNE]

K,
I'm also thinking...
I wonder if you have a bad battery? Even if the charging system isn't charging the bike should at run 60 mins at least.
I run my racebikes on total loss and can run almost as long at race speeds.
Wondering if you have something shorting out or the battery doesn't hold a load.
How long can you turn on the headlight and the battery falls below 11v? (test with the main ignition feed wire to the ballast unplugged or on a 400 pull the ignition fuse so you don't burn the points and coils)
Chuck

[Premiumjo]

Nice looking bike.
I once reversed the polarity when  connecting my battery and the rectifier was toast.
As Chuck mentioned, could be the battery.  I had one die suddenly in my SV but it still read 12.7V with no load. Just shorted out or whatever.

[pdxjim]

I might have missed the memo, but did you split the cases and do a full rebuild, or just change the engine oil and hope for the best?

[Membername]

It's charging!

To review:
0. Tested the rectifier as noted in the service manual, it tested bad.
1. Removed the brushes from the stator and tested the resistance between the two slip rings, it was 5.7. Also tested each slip ring to ground and it was not continuous. Wiring at the stator looks good.
2. Center bolt was magnetized with ignition key on, and the bike off.
3. Voltage on the green wire at stator-
Key on, bike off,  Left green wire 11.3 V, right green wire, 310 mV,
4. Make sure green wire is not shorted to earth on ohms.
Key off-Ohms in left green wire, 6.3.  On right green wire, 18.2 (black lead on battery negative). Short (continuous) from both green wires to case.  Short from green wires to screws.
Key on- no shorts from green wires to ground or screws, O.F ohms between green wires and battery (negative lead). 
5. What is the resistance between the different pairs of the three white wires, should be about 0.5 ohms. All are 0.6 ohms
6.  Test each of the white wires to ground to make sure it's not continuous.
None are continuous with the engine case.
7. Check to make sure white wires are not continuous with each other. 
Key on or off, all white wires at rectifier are continuous.  White wires at rubber boot connector (rotor side) are continuous with each other, key on or off.  (This is something I read I think in the aircooledrd forum. It seems to me they should be continuous.)
8.  Check to make sure battery hooked up right (leads not swapped).

Since all of the above checked out except the rectifier, I went ahead and put in a new reg/rec from economy-cycle, and now the bike is charging.  Thanks everyone for your help!

Karen