Charging System Fades

[Guest]

1978 GS550
As the bike warms up, the charging system slowly loses ground and finally barely keeps the bike running through the day. It gets especially bad if I slow down (driving through a city) but sometimes can catch up when I speed up again. As far as I can figure, something is heating up but I have no idea where to look.

So far I have replaced the R/R with an Electrosport part and a new stator; new ignition and coils from Dynatek as well. Also, a new headlamp from Candlepower (AMAZING how much brighter it is!!!) What else is there? Completely rewire the bike? Any help or suggestions would be greatly appreciated!

[tom203]

Start with something simple- do the Quick Test in this link. Note you must start with fully chsrged battery (use charger)- report all 6 items

http://www.thegsresources.com/_forum/showthread.php?164993-Charging-System-QUICK-TEST/page2&p=1272192#post1272192

do you know the wattage of this headlight? This replacement stator has 12 poles like the original or ???

[posplayr]

It sounds like a bad battery that will not hold a charge, but the first step of the Quick Test will test that.

When You say the charging system is "losing ground", you mean losing power not literally losing ground?

[KJL316]

As requested, I did the Quick Test and when the bike is cold (had not run in several days - battery fully charged on a charger), all the numbers were within normal limits. But after running for a few hours, I got home and ran the test again
1. key off - 12.29V
2. key on (lights on, coils off) 11.91V
3. at idle 1500rpm - 11.89V
4. at 2500rpm - 11.98V
5. at 5000rpm - 12.11V
6. key off - 12.29V

The new headlamp takes a standard H4 bulb at 55 watts and this is a new battery.

[KJL316]

It sounds like a bad battery that will not hold a charge, but the first step of the Quick Test will test that.

When You say the charging system is "losing ground", you mean losing power not literally losing ground?

Sorry, yes I meant not charging, though it seems to be able to charge somewhat but just not enough to keep up all day.

[posplayr]

As requested, I did the Quick Test and when the bike is cold (had not run in several days - battery fully charged on a charger), all the numbers were within normal limits. But after running for a few hours, I got home and ran the test again
1. key off - 12.29V
2. key on (lights on, coils off) 11.91V
3. at idle 1500rpm - 11.89V
4. at 2500rpm - 11.98V
5. at 5000rpm - 12.11V
6. key off - 12.29V

The new headlamp takes a standard H4 bulb at 55 watts and this is a new battery.

You are not passing the battery test. A battery at rest even a bad battery should be about 12.8V.

When you loaded the battery with the key on why are you saying the coils are off? That is part of the tests; the ignition should be on as normal.

Your charger is not doing what you think or your battery is already gone because of it.

Your charging system is not charging at all; none of your numbers are above 12.8V.

Granted a proper charging system should see more voltage output that what you have, but I would reserve judgment without seeing a test with a better battery. It could be for example your stator is gone but generating something but not enough to actually charge. Your charger is also a trickle charger and can not supply the required amperage to actually charge either.

To be clear, when I say "Charging" I am referring to the battery and you need at least 12.8V to push any current into the battery.

[tom203]

Yes, your battery is poor, your charger doesn't seem to do its job (at least with this battery). Your bike at one time had seperate rectifier and regulator- so this ES r/r likely replaced both of those. Did you wire the stator direct to r/r to skip old headlight loop bypass?