charging question

mmarm300 · Full Member Joined: Aug 10, 2009 Posts: 28

Im going through my failing charging system using the vault notes. I have not yet tried jumping the green wire to the battery yet bc i dont want to cut into wiring yet but this is what i have so far.

Brush getting 10.5 to 11+
3 white wires from stator are getting 6-7 vac on all 3
ohm check for same wires are .7 to .8 for all 3. (i know they should get battery voltage and .5 ohm)

the battery will charge to high elevens but no more and it loses voltage as the bike runs and eventually dies out (unless i have charger on it.)

By the way it is a stripped bobber project just running headlights and taillights. kick only (simple bobber wiring diagram)

Have i found my problem with the stator, or are these readings coming as a result of a problem elsewhere. I really apperciate the advise...thanks.

mmarm300 · Full Member Joined: Aug 10, 2009 Posts: 28

by the way its a 78 vs650

chexin51 · Posted: September 28, 2009, 8:21 pm Post subject: Re: charging question

6 - 7 volts white to white is way low - it should be 10 - 11 volts AC - these white wires are the outputs of your stator windings - possibly one or more of the windings have cracked insulation lowering its output.

I strongly recommend you start at the beginning and do the following:

1. check your battery after a full charge - 12.5 to 12.8 VDC is what it should show - a battery more than 3 years old is getting weak

Best bet is to search for an article called Curly's Charging System Troubleshooting Guide that will surely help

xs650temp.proboards.co...hread=3461

good luck

mmarm300 · Full Member Joined: Aug 10, 2009 Posts: 28

im working off that list i was just wondering if this is my problem since im getting those readings. Thanks

xsleo · Posted: October 1, 2009, 3:01 am Post subject: Re: charging question

With the ac volts you have and the white wire ohms, I would replace the brushes unless they are new or close to it. I would check the ohms of the rotor, should be 5 to 6 ohms. If your rotor or brushes are not good the stator output will be low.
You don't need to cut into the wiring to jump battery voltage to the green wire.
Use a wire long enough to reach from the battery to the brush.
Put an alligator clip on each end of the wire. Use a small one on one end with an insulating cover. Hook this end right to the green brush wire at the brush.
On the other end use a large one, large enough to hook to the positive battery terminal. Hook it to the battery.
This will send battery voltage straight to the brush. If the rotor, brushes, and stator are good the battery voltage will climb up. Don't let the voltage go over about 15 to 16 volts, the battery won't like it. If you have an electronic ignition it won't like the high voltage either.
When you jump the green wire like this the ac voltage will be around 20 volts. Thats what mine was at idle with the rectifier unhooked. If this all checks good the regulator isn't working.
I would get a Chrysler regulator and wire it in to replace your stock mechanical one.
If you are using Curly's charging guide, check out the Pamcopete's regulator and rectifier mods at the same site. The threads explain it better than I can.

xsleo · Posted: October 1, 2009, 3:18 am Post subject: Re: charging question

Just reread this post. If your rectifier has a bad diode the output will be low to. With one bad diode you will only be using two of the three legs of the alternator.
Check out the Pamcopete upgrades for the regulator and rectifer. Easy mods to do and less expensive than a new regulator and rectifier that is motorcycle specific.
I did it on my 75 and have a syeady 14.5 volts from any where much above idle, with the lights on or off. The turnsignals work great at idle.
Converting all the lights you can to LED is a great current saver too. The more current you save from other places can go to charging the battery.

mmarm300 · Full Member Joined: Aug 10, 2009 Posts: 28

thanks xsleo...ill give it a go and let you know

mmarm300 · Full Member Joined: Aug 10, 2009 Posts: 28

where can i find pamco pete's info, and you said jump green to positive? I thought curly's said to jump to ground? I have another thread below. I tried to jump to ground but blew my 10amp fuse. Im told it should be 20amp so im gonna replace and try again later...thanks again

gordo · Posted: October 1, 2009, 2:05 pm Post subject: Re: charging question

marm, check the rotor,as Leo said. Very common problem on these bike's.Chexin gave you a likn to the 650 garage, just do a little searching in the electrical section for pamcopete's cheap regulator setup.And the wire doe's go to positive +.

mmarm300 · Full Member Joined: Aug 10, 2009 Posts: 28

did the green wire jump test and nothing happened. Im getting battery voltage at the brown wire on the back of the key switch as well as at the positive brush. Did the rotor test and its in spec. I cleaned the brass rings and checked my brushes while i was there and I managed to break one of them so i ordered a new set. Found a cheap reg and bought that. We will see what happens. Thanks for the advise...ill be back with my results within the week when the replacement parts get here

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