Question about alternator/stator test

[baz666]

I've checked in the old Q&A and in the search function but I haven't been able to find a basic description of how to test the alternator/stator.

I recently bought an '83 GS750ESD. It's a great little bike but for a few niggling problems. The PO said the battery needed replacing. I took it out and charged it overnight and it seemed fine. I put it back in the bike and it was okay for a little while but eventually went dead. I assume it wasn't getting charged. I tried a different battery, same deal. I tested the solenoid, it clicks fine when I press the starter button. I checked the battery cables, they're fine as well.
So I'm thinking it is the alternator/stator.
So my question is, how do I test it and what do I look for? I have a multimeter.

Oh, since I've got your attention, my odometer and trip meter aren't working either and neither is my temp gauge. It appears somebody dicked around with the wiring behind the gauge unit. I haven't been able to find a manual for this particular model so if anyone knows where the oil temp wire runs from and to, I'd be much obliged.
thanks in advance,
baz

83 GS750ESD
81 Yam XJ650H Maxim

 

[Steve]

First of all,

There is a guy named BassCliff on this forum that has a little site of his own, where he has collected much of the collective wisdom.

On that site, he has links to many items, including the topic in which you are interested: The Stator Papers.

Grab your multimeter and your shop manual (BassCliff has some manuals available for downloading, too) and follow the guide.
You will find your problem rather quickly.

.

 

[TheCafeKid]

I've checked in the old Q&A and in the search function but I haven't been able to find a basic description of how to test the alternator/stator.

I recently bought an '83 GS750ESD. It's a great little bike but for a few niggling problems. The PO said the battery needed replacing. I took it out and charged it overnight and it seemed fine. I put it back in the bike and it was okay for a little while but eventually went dead. I assume it wasn't getting charged. I tried a different battery, same deal. I tested the solenoid, it clicks fine when I press the starter button. I checked the battery cables, they're fine as well.
So I'm thinking it is the alternator/stator.
So my question is, how do I test it and what do I look for? I have a multimeter.

Oh, since I've got your attention, my odometer and trip meter aren't working either and neither is my temp gauge. It appears somebody dicked around with the wiring behind the gauge unit. I haven't been able to find a manual for this particular model so if anyone knows where the oil temp wire runs from and to, I'd be much obliged.
thanks in advance,
baz

83 GS750ESD
81 Yam XJ650H Maxim

Your trip ) and odometer are driven by your speedo cable.. Unless the 83 750 went all 'lectric and fancy on us.. I am not completely familiar with them, tho i seem to remember them having an electronic tach, and cable driven everything else (like my 83 1100ESD) As far as your charging issue, I too suggest going through the Stator papers.. GSs have a penchant for spitting out their charging systems.. usually the Regulator/Rectifier units, which can sometimes lead to the stator frying out.. (it happens, dont hate on the bike for it) The oil temp wire should run down the harness and connect to ythe back of your pressure sensor block on top of the tranny side of the cases (under your carbs) BUT, as I type that, I dont remember if the 83 motor had one of those or not.. pretty sure, but if it does, you'll see it.. it sticks out the top of the cases under your carbs...looks like a little nipple.. heh. .. there should be a PINK wire that attaches there i do believe...

 

[trippivot]

#1 . fill / check the water in the battery
#2. slow charge the battery (2 amp 6 hours)

#3 . load test the battery


never assume anything!! batteries are the weakest link in a 70'~ 80's bike.

1 a year is very common no matter what you do

 

[Steve314159]

In general, a battery will read with your multimeter with the bike off between 12.5 and 12.8 volts. If you start the bike and read the voltage at the battery it should be between 13.8 and 14.4 volts. Temperature is important, with the voltage being .1 or .2V lower at cold temperatures for just the battery.

Charge up your battery. Start your bike a few times and quickly turn it off. Wait ten minutes and check the battery voltage. If it's less than 12.5 you have a bad battery. Start the bike and measure the voltage at the battery - If it's not above 13V minimum you have a bad charging system.

 

[baz666]

Thanks to everyone for all the excellent advice and info. I belong to a similar forum for the XJ650 I own and without the great people on these kinds of forums, I'm sure very few old bikes would be running - certainly not mine!
thanks again,
baz