charging system trouble, please help

[dschmitta]

Hey everyone,

Have 1980 xs1100g. Noticed while riding the other night, the front headlight appeared dim and flashers were only working intermittently. Stopped next day at yamaha dealership. Used v-meter on battery. Tested at around 12.4 at start and idle. Problem is, still tested same at 5 thousand R.P.M. He said stator had to be bad. Does this sound correct? his price was $541.00 for this bad boy, Whew. Is there anything else that might come to mind to check before replacing this part? If not, does anyone know of someone who has one cheaper? Thanks for any help.

[Rasputin]

First off Welcome to the site. You will find good info on your bike here.
There are a few possibilities that come to mind.
One is the wires and connectors which come from the stator. They may be corroded or loose, a good cleaning will often help this. This connector is behind the fuse panel under the seat.
There could be issues with the regulator/rectifier. Tests for both the reg/rect and the stator can be found in the manual. There is a downloadable manual available on Catatonicbug's page, just click the link in his signature to download it. It is a very valuable tool to have in your possession.
The search tool will help immensely but sometimes you have to try different wording to find what you really want, DAMHIK.
I am certain many will chime in to help that know way more about electrical than I do.

[dschmitta]

Thanks. Will definately check these out. I live up in PA, and the weather is nice today, so I'm going to go out and work on bike in the sun. Thanks again

[dschmitta]

Thanks. Will definately check these out. I live up in PA, and the weather is nice today, so I'm going to go out and work on bike in the sun. Thanks again

This was for you RASPUTIN. Didn't mean to leave your name out. Sorry about that

[cywelchjr]

The stator being bad is really not very likely. The connectors could be bad or dirty and cleaning those up will certainly not hurt anything, but the most likely culprit would be the regulator/rectifier. Now they replacement units can be pricey if you go for new, and if you do that you should consider getting one of the upgrade units from geezer on this forum. However, I had good luck picking up a used unit off ebay for about $15 almost 2 years ago, and it's still working just fine. I would download the manuals from catatonic bugs website (the link would be in any of his posts) and do the tests with the meter on the stator, but in my experience, the resistance of the stator can be as much as 40% off from what the book says and still have everything work great as long as there are no shorts or opens.

[b.walker5]

Golden Rule...

... Start with the easy stuff first and do one thing at a time. don't jump to any conclusions without thoroughly ruling out other things.

Start with the connector with the three white wires behind the fuse panel. This is a notoriuos trouble spot. Look for corrosion, bad connections, broken wires, and a connector block that is crumbling and looks melted.

Disconnect the plug and test the alternator leads (3 white wires) for continuity, and resistance. Test between each lead, and between the leads and ground. Cy is right, the value may be different to the stated value in the manual but between each lead they should be similar. There should be no circuit between the leads and ground.

Test between the brown and green wires in the smaller plug also. This is the feild coil for the alternator and if it's bad you wont get any charging happening. Once again, test between the leads, and down to earth. The manual has the approximate values you are looking for.

If these things check out okay, then it's time to start thinking regulator/rectifier. Test as per the manual, do this a couple of times and compare results before deciding it's crook.

Personally I have experience a bad plug, a burnt out stator and an open circuit feild coil, but never a crook rectifier. Plenty have though. Theres a tech tip here somewhere on checking and resoldering dry joints in the rectifiers, which is also a known trouble spot. Look for it on the tech tips section on the home page of the site.

Hope that helps

Regards
Brian

[dschmitta]

thanks everyone. will start with basics (downloaded manual) and see where she goes. not to good with electrical terms about testing between stuff. sorry, just plain simple with it, could anyone explain how to go about that. sorry and thanks

[b.walker5]

Okay, first things first. Get a test meter, digital or needle type, it makes little difference, and set it to the ohms scale (Greek Omega symbol). Touch both leads together and check the meter operates. You should get full scale deflection of a needle type,or large numbers and/or infinity symbol from a digital.

The three white wires from the alternator are all connected at one end. Think three wires all twisted together at one end and open at the othe ends, like a 3 leg star.

Number, or identify your wires as 1,2 and 3. Connect your meter leads to 1 and 2. Record the reading. What you are doing is testing the resistance down through wire 1 to the centre point and back out wire 2. Then take the test lead off wire 1 and connect it to wire 3. This tests the remaining wire. As a final test take the test lead off wire 2 and connect it to wire 1. This confirms continuity through all three legs of the alternator and all reading should be similar.

Now take one test lead and connect it to a metal part on the bike (ground), or the negative lead of the battery. Take the other test lead and connect it to each of the three wires of the alternator in succession. This is testing for a short circuit to ground and if good you should get no reading.

For the feild coil simply test from the brown to the green wire and look for around 1.5 ohms (from memory). If you get no reading, either a wire is broken or the coil is shot. Test from either wire to ground to look for a short circuit.

Let us know the results and we can add further if required.

Brian

[dschmitta]

Okay, first things first. Get a test meter, digital or needle type, it makes little difference, and set it to the ohms scale (Greek Omega symbol). Touch both leads together and check the meter operates. You should get full scale deflection of a needle type,or large numbers and/or infinity symbol from a digital.

The three white wires from the alternator are all connected at one end. Think three wires all twisted together at one end and open at the othe ends, like a 3 leg star.

Number, or identify your wires as 1,2 and 3. Connect your meter leads to 1 and 2. Record the reading. What you are doing is testing the resistance down through wire 1 to the centre point and back out wire 2. Then take the test lead off wire 1 and connect it to wire 3. This tests the remaining wire. As a final test take the test lead off wire 2 and connect it to wire 1. This confirms continuity through all three legs of the alternator and all reading should be similar.

Now take one test lead and connect it to a metal part on the bike (ground), or the negative lead of the battery. Take the other test lead and connect it to each of the three wires of the alternator in succession. This is testing for a short circuit to ground and if good you should get no reading.

For the feild coil simply test from the brown to the green wire and look for around 1.5 ohms (from memory). If you get no reading, either a wire is broken or the coil is shot. Test from either wire to ground to look for a short circuit.

Let us know the results and we can add further if required.

Brian

Thanks for info. much apreciated. Will do tests and update with what I find

[dschmitta]

Guess what I found?

Got all tools ready, meter,etc. Pulled cover, found three white wire connector, and bam. Plastic is totaly crumbled from top bottom on the underside, wires visible and nasty with a wire showing even going into connector. How I go about fixing this bad connection? Just cut out and try to find differnt connector? Not sure what to do. Any help greatly appreciated.

[natemoen]

There is a member on the forum here named geezer. He has all the correct connectors. Or you could use regular spade connectors, but the connectors would be better in the long run.

[Rasputin]

Just might have saved yourself 500 bucks for a little investigation time. Great! There are a lot of connections of these bikes that can usually use a bit of cleaning, check out all of them as you get time. Hopefully the crumbled 3 wire connector is the problem.

[dschmitta]

If I had to fix without proper connector, what would be easy and best way to do that? I am a novice with electrical items. Also, did check brown and green connector and meter was right on, just cleaned and put some dialectic grease on and put back together. Thanks everyone

[DGXSER]

Go to any auto parts store and bring one end of your existing connector with you. They can help you find one that is close in size and shape with three pins of some type and capable of the load. I find that locally Napa and or KOI has alot more of these than anyone else.

Only draw back is if you find your alternator goes out and need to replace it, you will need to transfer your "new" connector end to the "new" alternator.

[Rasputin]

Easiest would be butt connectors crimped on but that is not the best by far. There are several ways to do it from soldering to using the correct connector available from Geezer. I would simply do what I had to for now to check that it was working. I then would contact Geezer and get the correct connector. You can do it any way that you are comfortable with, just do not do the PO's poor excuse of twisting them together and black taping them. That would be good to check that you have charging only, after that you need a good fix.