GS750 Died, then wouldn't start again.

[Guest]

Just on a normal ride today, I slowed down to turn and as my rpm's dropped the bike shut off. Tried to restart it but it barely turned the starter over.

Had to jump it, ran it home. Here are my quick test results:

Key off: 12.0 volts
Key on: 11.5 volts
Idle: 12.1 volts (bike wouldn't start again right after my ride, I had to charge it for a bit.)
2500 rpm: 12.2 volts
5000 rpm: 12.0 volts
Key off: 12.0 volts

Since every voltage is low does that mean my battery is bad? I do notice revving from idle my headlight brighten a bit and then dim a bit as I go back to idle. Not sure what this all means. Electronics have always confused me.

Thanks!

[tkent02]

Your charging system isn't doing much. No reason to suspect the battery at this point, it's just not getting charged. The battery itself may or may not be good.

Have you done any maintenance at all to the electrical system? I would guess not because of this last statement:

Electronics have always confused me.

Time to learn.

[scottyknows50]

Would that be a rectifier problem since the power is not going to the battery?

[mrbill5491]

Nope, probably means your charging system probably bit the big one. Do a search lots and lots of info on this subject.

[scottyknows50]

Just an update, changed out the rectifier and this is how it is testing out:

Off: 12.8 volts
Key on: 12.2 volts
Idle: 12.8 volts
2500 rpm: 13.3 volts
5000 rpm: 13.1 volts
off: 12.8 volts

Other than a higher charged battery, I guess I didn't change much. Bike will still die if it drops down to idle after riding for a bit, but now at least I have been able to restart it on the go. I guess I"ll look into stator problems next?

Thanks for any advice.

[posplayr]

Would that be a rectifier problem since the power is not going to the battery?

The battery is marginal, but you are generating some power but it is low.
i would test the stator using the revised phase b tests. Make sure you do leg to ground tests in addition to leg to leg at 5k