Battery dead after first ride...

[benjo]

Hi all!

I have a 1981 GS450 that I have been working on for a while. Today I finally got it into shape to take it for a ride. After about a 30 minute ride, I turned off the bike. When I attempted to to start up the bike again the battery was flat and I had to push start it. The bike had been sitting in my garage for awhile and I had been starting it a lot to test the carbs, without running it for a long time. But why would the bike start up perfectly at first, and then after a 30 minute ride the battery be completely flat?

Is the most likely culprit:

1) Low battery to begin with - just need to fully charge it
2) Relay Rectifer not properly working (looks old, but not stock)
3) Stator (hoping to god it is not this as getting one in South Africa will be impossible)
4) A combination of the above

If anyone has had the same issue or can give me a run through on how to test each of the above components with a multi-metre, that would be super helpful.

Thanks!
-Ben

[Mosquito13]

There is a great how to on doing a simple testing the electrical system try a search to find that post, what is the current when running at the battery? How old is the battery?

[Nessism]

A GS bike that's not charging the battery? Who knew?

Oh wait, I seem to remember reading about that about 1000 times previously. Humm.

[posplayr]

Hi all!

I have a 1981 GS450 that I have been working on for a while. Today I finally got it into shape to take it for a ride. After about a 30 minute ride, I turned off the bike. When I attempted to to start up the bike again the battery was flat and I had to push start it. The bike had been sitting in my garage for awhile and I had been starting it a lot to test the carbs, without running it for a long time. But why would the bike start up perfectly at first, and then after a 30 minute ride the battery be completely flat?

Is the most likely culprit:

1) Low battery to begin with - just need to fully charge it
2) Relay Rectifer not properly working (looks old, but not stock)
3) Stator (hoping to god it is not this as getting one in South Africa will be impossible)
4) A combination of the above

If anyone has had the same issue or can give me a run through on how to test each of the above components with a multi-metre, that would be super helpful.

Thanks!
-Ben

Recharge your battery and do a "Quick test"

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

[Redman]

The quick Test is to confirm if entire charging system is working or not.

If you want to check the stator you are concerned about: that test is to disconnect it, and check voltage across each two legs at about 4000 rpm. All three reading should be upper 60s or near 70 volts AC.

[Nessism]

The quick Test is to confirm if entire charging system is working or not.

If you want to check the stator you are concerned about: that test is to disconnect it, and check voltage across each two legs at about 4000 rpm. All three reading should be upper 60s or near 70 volts AC.

Realize of course that the no-load AC voltage test is not definitive though. A stator with good AC output still may not put out a proper amount of output to achieve the desired 14.5VDC charging voltage at the battery.

[posplayr]

Realize of course that the no-load AC voltage test is not definitive though. A stator with good AC output still may not put out a proper amount of output to achieve the desired 14.5VDC charging voltage at the battery.

The leg to ground tests at 5K RPM seem to be the best without getting a Megger

These are getting cheap enough that you can dispense with most of the 5K RPM revving and just go leg/ground with these.

https://www.ebay.com/itm/Digital-Insulation-Resistance-Tester-Megger-MegOhm-Meter-1000V-0-1-2000M-VC60B/120844049506?epid=781695260&hash=item1c22dddc62:g:gXQAAOSwMmBVwHbk

[Nessism]

The leg to ground tests at 5K RPM seem to be the best without getting a Megger

These are getting cheap enough that you can dispense with most of the 5K RPM revving and just go leg/ground with these.

https://www.ebay.com/itm/Digital-Ins...QAAOSwMmBVwHbk

So do an IR test then? What would be a good passing result?

What about a dielectric test? Any value?

[posplayr]

So do an IR test then? What would be a good passing result?

What about a dielectric test? Any value?

A Megger is the traditional test equipment used to test armatures and winding and you can buy one for $50.

BTW an Insulation Resistance (IR) tester is a Megger

https://www.hunker.com/13414113/how-to-use-a-megger-insulation-tester

A dielectric tester probably is similar, but not sure about the voltage ranges.