GS750T charging system problems, new stator may have been DOA???

[gjexm]

Hi guys,

We have a 1982 GS750 that has been having the same charging problems many of you have experienced. We replaced the battery, the R/R, and the stator (they all needed to go). After replacing all that, we rode off on the bike and two or three hours later the battery was dead.
I followed the stator papers step by step and all was well until measuring the AC voltage between pairs of stator output wires. Two pairs read 60V at ~4500rpms (the same), and the third read 1.5V.

Is it more likely that my new stator was DOA? It was ordered from DB Electronics for about $50.
Or is there a chance that something on the bike is killing stators? Is there anything else I should check before I just try replacing the stator AGAIN?

We tried a few things since putting in the new stator, including bypassing the wiring for a non-existent headlight switch between the stator and R/R, and running the R/R ground directly to the battery negative.

And here's another question that I'll ask only because my knowledge of electrical systems is really spotty: I know on pre-1980 bikes one leg of the stator was run through to a headlight on/off switch on the assumption that you didn't need all three phases if the headlight wasn't on. Is it possible to make my stator work in its current state if I don't run the headlight? I know this isn't a long-term solution, just curious if it's possible.

Thanks for your help, I've learned so much from lurking in these forums already!

 

[posplayr]

Charge the battery and do the Quick test in my signature . Also review gs charging health to see if you missed anything. You can report the numbers for s diagnosis.

is you think you did the revised Phase b correctly change the stator. If you want to know about r/r read gs stator also in signature.

 

[gjexm]

The battery is not in the bike right this second, but I have done the quick test and can't find where I wrote down the numbers (ugh).
These are the numbers I remember, is it enough to be helpful? The battery was brand new and charged.

Key off: 12.75V
Idle: 12.33V
2500rpm: 12.40V
4500rpm: 12.41V

 

[posplayr]

The battery is not in the bike right this second, but I have done the quick test and can't find where I wrote down the numbers (ugh).
These are the numbers I remember, is it enough to be helpful? The battery is brand new and charged.

Key off: 12.75V
Idle: 12.33V
2500rpm: 12.40V
4500rpm: 12.41V

OK I'll take you word it is charged, then you probably have a bad stator. Did the system ever charge over 13V? If so it is probably burned out. I assume you never got a series R/R?

 

[gjexm]

I never saw it charge over 13V. The battery was dead after the inaugural ride, so I am lead to believe it never charged at all.
Is it likely that my new stator arrived DOA?

The new rectifier was ordered from here: http://www.regulatorrectifier.com/catalog/1982-SUZUKI-750-GS750T-REGULATOR-RECTIFIER

 

[posplayr]

I never saw it charge over 13V. The battery was dead after the inaugural ride, so I am lead to believe it never charged at all.
Is it likely that my new stator arrived DOA?

The new rectifier was ordered from here: http://www.regulatorrectifier.com/catalog/1982-SUZUKI-750-GS750T-REGULATOR-RECTIFIER

Sounds liek it never worked, you would need to remove it and reinspect it for physical damage that might have shorted a winding or evidence of burning; otherwise it would have been a factor defect.


That R/R is very likely a poor choice.

 

[gjexm]

Any chance the R/R could have killed the new stator?

 

[posplayr]

Any chance the R/R could have killed the new stator?

If it never charged not likely. Even in the worst case I could imagine you should at least get 1-2K miles on a good stator that was burned to a chrisp

 

[gjexm]

Just to clarify, you're saying if the stator was good out of the box I should have gotten a couple thousand miles before it burnt up?
Definitely sounds like DOA.

Thanks for your help!

 

[posplayr]

Just to clarify, you're saying if the stator was good out of the box I should have gotten a couple thousand miles before it burnt up?
Definitely sounds like DOA.

Thanks for your help!

The stator is just heavy wire with an epoxy coating. You would have to physically damage it (crush wires under a cover/guide) or burn it.