Weak charging

silver6 · Full Member Joined: May 01, 2009 Posts: 45

Still having charging problems. Getting some sort of charge, but weak and it can't keep up.
any suggestions? My brushes are about 9-10mm and are within spec. Could this be my problem? Checked all the other possible scenarios and bench tests. Please help!

knightrider · Posted: July 23, 2009, 3:12 pm Post subject: Re: Weak charging

You have a good fully charged battery? stators good?
no other changes made recently that could be causing the issue??

silver6 · Full Member Joined: May 01, 2009 Posts: 45

Battery kept on a maintainer, all bench tests for rotor/stator assembly tested good, regulator good to my knowledge(need to do the hot to ground jump to verify). What do you think?

Retiredgentleman · Posted: July 23, 2009, 8:14 pm Post subject: Re: Weak charging

If you hold a .003" feeler gauge about a 1/2" from the alternator (with the small cover off), does the gauge get pulled over to the alternator when you turn the key on?

Buy some new brushes and clean up the slip rings with some very fine sandpaper or emery paper.

silver6 · Full Member Joined: May 01, 2009 Posts: 45

Retired, feeler gauge does nothing. To fill you in if I haven't, '75 with what I believe to be an '80 and up reg/rec combo, minimal wiring, and pamco. Checked rotor windings, and checked resistance on reg/rec, checked for voltage drop on positive brush(has been isolated with nylon screws) and with just key on is at 12.34 with battery voltage at 12.65. What have I done wrong? Is the reg/rec the right one for the '70-'79 bikes and I assumed wrong? Really want to get this thing figured out! Thanks for the help in advance!

Retiredgentleman · Posted: August 6, 2009, 12:19 am Post subject: Re: Weak charging

OK, you need to find out why you have no magnetic field from the rotor. You say you have 12.34 volts at the positive (right) brush. Maybe you had the negative meter lead attached to ground for this test.

Perhaps your voltage regulator is not supplying a negative voltage to the left brush. Connect the meter positive lead to the right brush as before, but this time connect the meter negative lead to the left brush. When you turn the key on you should measure 10 to 12 volts.

xjwmx · Posted: August 6, 2009, 9:59 am Post subject: Re: Weak charging

silver6 wrote:

My brushes are about 9-10mm

That's borderline too short. Or maybe plain too short. The voltage gets lower and lower as the brush wears. When mine got to about 7 - 9 mm there was below 13v at any rpm. New brushes cured it. If it won't pull the feeler gauge blade over you have another issue too though.

silver6 · Full Member Joined: May 01, 2009 Posts: 45

Guess I have another issue. What would cause no magnetic field? Have something to do with the reg/rec? Rotor tests good. Probably did have the ground probe on the ground. At work right now and can't check. If I don't have 10-12 volts across the 2 brushes what does this mean? I really appreciate the help!

jayel · Posted: August 7, 2009, 1:12 pm Post subject: Re: Weak charging

since the E/M field is created electrically by the stator , if your rotor checks good...... check the stator

Retiredgentleman · Posted: August 7, 2009, 2:40 pm Post subject: Re: Weak charging

If you have no voltage across the 2 brushes it may mean that the rec/reg unit is not working. However, it could also mean that you have a rec/reg unit for the 70 to 79 years, which is the opposite polarity.

If you measure no voltage, try this: Disconnect the wire (battery supply) on the right (+) brush and insulate it so it can't short to ground. Connect a wire from a good ground to the right brush. Now run the engine and measure the battery voltage at idle and at 3000 RPM.

silver6 · Full Member Joined: May 01, 2009 Posts: 45

I'll check it and get back with you when I get home in the morning. Before I isolated the brushes and changed the wiring, it wasn't charging then either. I thought maybe the guy I bought the bike from bought the wrong reg/rec for the year of bike. Is there no way to identify the reg/rec? It seemed to me he got tired of messing with it and wanted to move on. I'm not there yet. Not a smart man, but can follow directions and get pretty anal about it until I figure it out. Thanks for being patient retired!

xsleo · Posted: August 7, 2009, 9:34 pm Post subject: Re: Weak charging

Jayel, The e/m field is created by the rotor, not the stator. When the regulator turns the rotor on and the rotor spins, the six fingers that wrap around the rotor core, create positive and negative fields around the stator. These fields create the AC current in the stator, which flow through the rectifier and are converted to the DC current to run the bike.
On the early mechanical regulators, the regulator reads the battery voltage on the brown wire. If the voltage is below the preset it will turn the rotor on by sending power to the brushes on the green wire, in one brush through the rotor , out the other brush to ground. One way to check the rotor is to hook a wire from battery positive to the hot brush and ground the other, this bypasses the regulator and puts full battery voltage to the rotor. If the rotor is good it will pull in the feeler gauge.
On the later regulators the battery voltage is still read on the brown wire. To turn the rotor on battery voltage is sent to the brushes on the brown wire, through the brushes and rotor and out on the green wire to the regulator and grounds there. Check the same way.
If you hook the jumper wires on while the bike is running, the battery voltage should climb up. Don't let it get over 15 or 16 volts, to much for the battery. If this gets a charge you can use the rectifier part of the reg/rect you have and just hook a Chrysler regulator to the brush wires, and ground the body of the regulator. The battery box is not a ground.

silver6 · Full Member Joined: May 01, 2009 Posts: 45

Ok, checked the voltage across the brushes with the key on only. Got just above 3 volts! Does this mean the reg/rec is bad? When I bought the bike he had it mounted on a tab that was welded to the frame. He said he hit a hard bump and it snapped and the reg/rec assembly landed hard on the frame, etc. Could this have ruined it? Destroyed some diodes maybe? Hasn't been working since I don't think.

silver6 · Full Member Joined: May 01, 2009 Posts: 45

Well, just put on a different reg/rec that I know is from an 80 model and now I have no voltage across the brushes with the key on. What the h"&*% is going on? Why can't I get this right? Rotor is good and stator checks out. I can wire something up and have been over my wiring 100 times. Any suggestions? Ready to sell if I don't get this figured out!

xjwmx · Posted: August 20, 2009, 8:38 pm Post subject: Re: Weak charging

If it was stock wired, theres a fairly good troubleshooting chart for charging in the manual, for the 80 and up models. I think it's in the "H" supplement pdf. Sorry don't have a link, but might be in the Vault.

silver6 · Full Member Joined: May 01, 2009 Posts: 45

It's chopped wiring that I cleaned up a little bit. I know it's wired right. This isn't the first time I have done something like this. I'm not saying i have never messed something up before, but pretty sure it's right. Just getting frustrated I guess and want this thing resolved. Anybody near Frankfort, Ky that might be able to help?

silver6 · Full Member Joined: May 01, 2009 Posts: 45

Well, with the new reg/rec still have no voltage across the brushes, but battery while running is up to 12.9 volts at any rpm. Still not charging, but something changed! Anybody have any more suggestions? Sorry to beat a dead horse, but need help!

jayel · Posted: August 26, 2009, 10:18 pm Post subject: Re: Weak charging

is the reg/rec grounded?

Retiredgentleman · Posted: August 26, 2009, 10:32 pm Post subject: Re: Weak charging

You said you had 12.3 volts on the right brush, before you changed to a different rec/reg unit. You should still have that same 12.3 volts. Find out why you lost that 12.3 volts.................broken wire??.........bad connector??

silver6 · Full Member Joined: May 01, 2009 Posts: 45

I have no voltage across the brushes. Had about 3 volts with the other reg/rec. I do still have battery voltage from brush to ground. It's gone up about 1/2 volt to almost 13 volts. Better than before, but still not at 14.5 at battery While running. At about 12.89 volts at idle and only goes up to about 12.93 volts. Could I indeed have a reg/rec for 70-79 bikes? Still need to try and re-ground the right brush to see if it will charge. Have a small amount of "slap" now, but have to be about 1/4" away from the rotor nut.

xsleo · Posted: August 30, 2009, 12:12 am Post subject: Re: Weak charging

Well that's a step in the right direction.
One test of the rotor is to apply battery voltage directly to the rotor.
With the pre 79 setups you hook a fused wire from battery positive to the green wire at the brush, with the other brush grounded.
With the 80 and later setup you just ground the green wire. Both of these methods bypass the regulator.
With yours and not being sure which you have I would unhook both wires from the brushes. Using a fused jumper wire from the battery to one brush, and a jumper wire from the other to ground. This will send full battery voltage to the rotor, this should draw the feeler gauge strongly against the case or rotor mounting nut. If you start the bike with this hookup the battery voltage should increase. Shut it off if the voltage goes over 15 -16 volts, the battery won't like it and it may cook the pamco ignition.
If this test hookup gets a good result, it means the regulator is wired wrong or is bad. I know with my Chrysler regulator, hooking it with the green and brown wires reversed will burn it out.
If your reg/rect is from an 80 or later bike you need battery voltage hooked to the brown wire of the regulator and the brush with the 3 nylon screws. The green wire from the regulator to the other brush. Any other way and it won't work.
If it is setup for the pre 79 models The green wire from the regulator will hook to the green brush wire, the brown wire to battery voltage. the other brush to ground.
You can try hooking it up both ways. If one way charges great, if not go to advanced auto and get an R296Z regulator, cost about $16.
ount it any place you want. I mounted mine on the battery box where the stock one went on my 75. I ran a ground wire from one mount bolt to the battery. Hook the green wire from the brush to the upper left connector. The brown from battery voltage to the lower center connector. With this regulator you need the nylon screws.
I have a pic showing the mounting and wiring.

silver6 · Full Member Joined: May 01, 2009 Posts: 45

Thanks xsleo. Got fed up and finally built the one like you have. I haven't been able to run it yet because it was about 2 am when I finished. I finally have the magnetic field and a whole bunch of slap, but still have no voltage across the brushes at the brush holder with just the key on. Someone explained to me that there needed to be about 10 to 12 volts. Wouldn't it have to be running to see that? Anyway, I closer than I was before. I know my new setup works now so if there are any problems I can troubleshoot the rest of the system. Thanks for all the help from everyone. This bike would have driven me insane without the people on this site that have already "been there and done that".

Retiredgentleman · Posted: August 30, 2009, 11:26 am Post subject: Re: Weak charging

If you now have a strong magnetic field, that means you must have voltage across the brushes. Its the voltage (current flow) that produces the magnetic field. Check out your VOM (and leads) operation by measuring a known voltage somewhere else.

silver6 · Full Member Joined: May 01, 2009 Posts: 45

Well, been working on it again today. Retired, I have had this meter for years and have used it on countless projects so I trust it. With the new reg/rec combo with the chrysler regulator and radio shack rec's it is missing bad! Acts like it wants to just shut off and on when I give it some gas. Has anyone ever had this happen? Also, without the key on I still have a magnetic field on the rotor nut. Sounds like a wiring problem, but it has to be wired right. I've been over it 100 times!

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