Crazy charging problem!!!

Alright guys, I'm brand new to this forum! I purchased a 1983 Midnight Maxim 750 for 300 dollars a month or two ago. I was told it only needed a stator (I know the guy, so I trusted that's honestly what he thought). I rode it for a while and the battery never died on me.. Until I was 40 miles or so away from the house.

I put a junkyard stator in for 60 dollars, and that didn't fix the problem. Bike still dies while I ride it. First the turn signals won't work, then the gauges won't light up, then the spark gets weak and it just dies. When I try to crank it over after it dies, the battery is completely flat.

I decided the battery looked a little bad, acid levels were pretty dang low, and god knows how many years it was stored outside with. Figured I couldn't lose, so I purchased a new battery.. guess what? It didn't fix the problem. :?

I then went back on the stator. It said it worked (In the eBay description), but I just figured that it looked so old/dirty/crappy I may as well replace it. 140 bucks later, I have a brand new stator in my hands. Put it in the bike today, (the battery was fully charged from my battery tender once again) and went on a ride. After 50 miles (has happened all three times.. fully charged battery gets me 50 miles) the bike dies again. First the turn signals, then gauge lights, then the ignition system.

So here I sit, confused as all heck.. hoping I didn't spend 220 bucks I didn't need to spend.

If ANYONE has any input.. I'd love to hear it. I'm at a loss for what could be wrong. Just got my bike permit a week ago and I love to ride the bike. When it runs, it runs beautifully! I'll post pictures and stuff after I get this sorted out.

 

Hey-welcome to the site, neighbor! Electrical probs can be darn frustrating. Does your bike still have the original fusebox? Im not sure if this is related to your problem, but an upgrade to a blade-style fusebox is a must for these 30 year old motorcycles. The old glass fuses can be the cause of many mysterious electrical problems.
This is a great site for information on XJ's. Theres many members here who know these bikes inside & out. Hopefully one of the more knowledgable folks will chime in here with more suggestions. Also, if you need parts, look no further than our man Chacal here @ XJ4ever. His prices & service cant be beat. Good luck to ya.

 

Thank you! Yes, I still have the original fuse box, glass fuses and all. They don't look too bad, but I suppose there's always the possibility.

 

Did you check the brushes while you had the alternator apart? Could have a bad regulator/rectifier, fuse box or faulty wiring. If you don't know much about electrical systems, read up on it or find someone near you that does. It would help to have a volt meter and know how to use one. If you don't have a manual, get one, it'll have a wiring diagram in it. Good luck.

 

Also might be a faulty regulator/rectifier unit. Or a loose/damaged ground strap or a short in a wire. Just tryin to throw some ideas out here. Whatever happened to SQL Guy? Havent seen him around for a long time.He's a good one for electrical problems.
If you dont have a manual, better get one. Best investment you can ever make for your bike.

 

Do you have a multi-meter? It is a good tool to have, guessing on parts can get expensive.
There are 3 main parts to your alternator, rotor, stator, regulator. Each part needs to be tested. A good repair manual will show you how. Alternator brushes need to be the proper length. The alternator wiring connections are another common problem for failure.

 

Herein lies your answer.

DIAGNOSE. Don't just start throwing parts at it, especially an electrical problem. I hate to be the one to tell you this, but actual stator failures are rare, you probably did buy a new one unnecessarily.

More likely you need new alternator brushes, or have a regulator/rectifier or wiring/connection problem.

Start with the large white plug-in connector coming off the regulator/rectifier unit; unplug it and check the condition of the connectors.

Check your alternator brushes; clean and polish the surface of the rotor where they ride.

And don't trust that original fusebox.

 

Your charging system needs to put out the right voltage. You need a manual to test it properly and pin point the problem.
The Library has manuals, that you can photo copy the part you need if you don't want to buy the whole manual.

MN

 

You have a library that LETS you photocopy books? Odd...

 

A quick check on your regulator may speed up the problem solving. start the bike and measure voltage accross the battery terminals you should get around 13.5 to 14.5 volts DC, when everything is working properly.

Anthing over 14.8 output indicates your regulaotor/ rectifier is suspect. and start by checking at the plug in connector for bad or dirty connections

As others have said before electrical probs are a pain and their is lots of info on the site.

 

Yep here in MN they have nice big copiers you can lay the books on. We have copied many wiring diagrams from service manuals they have. The St Paul branch downtown has manuals that go way back to the 50's . They won't let you check them out at all.

MN

 

Not odd here either; I never could have got the transmission out of my '68 MGB were it not for the public library. (Granted that was about 40 years ago, but AFAIK it's still ok.)

You missed a detail. Start the bike, REV IT UP TO ABOUT 2300 RPM, then measure the voltage across the battery terminals.

At idle, the charging system hasn't "come online" yet. It's not at full output until about 2K.

 

Thanks for the input everybody, this is the brother of the OP. We do have a volt meter at hand so we will be doing some checks with that. (Hopefully later tonight)

I do have the service manual for my '82 xj1100j, so maybe we will try and look through that to get some more ideas on the whole troubleshooting of the charging circuit.

What should we be looking for with the alternator brushes to see if they need to be replaced?

 

They have wear lines on them. If they are getting close to those lines just replace them and be sure to clean the surface they ride on.

MN

 

Alright, brother of the OP here again. We went out with a multimeter and tested the voltage across the battery when increasing the rpm's from idle and the voltage started at 12.14 at idle and decreased as the rpm's increased. The rpm's decreased by a few tenths.

We took a look at the alternator fins (I believe) and took a couple of pictures. They did look like they had a coating of gunk on them that would increase the flow of things if it were gone.

Oh and there were a few scratches on one or two of the fins.


A bit closer up


Fusebox (old glass one) Looked fine and would not contribute to the problem we are encountering since the "ignition" fuse would not let the bike start/run at all if it/the connections were bad.

 

Well... It seems like I may have just figured out the problem.

Alternator Brushes. BrusheS signifies plural.. But in this picture you will notice there is only one 8O





So the plan now is to order a new set and I am very convinced it should be good to go from there, also possibly take some very fine grit sandpaper to the alternator fins that have the gunk on them.

 

How do the brushes look. They should be more than 10mm which is the wear limit. If they are close to that measurement you'll need new brushes.
You see where the brushes ride. You can lightly sand that and polish that surface so the brushes make real good contact.
Once you have made sure that is in good condition . Locate the three wires coming up from the generator. There is a white plastic connector that likes to melt. Make sure that connection is in good shape and please report back.
MN

 

MN i think you missed the last post one of the brushes appears to have snapped off.

 

I must have been writing when that came through. Oh well it's looks like he found the problem.

MN

 

Thanks for all the help guys! But does anyone know anything about the alternator rotor fins from the first page? They looked a little iffy to me, do they need any attention?

 

Those fins do nothing for the process of generating electricity. The circular contacts on the face of the rotor (where the brush(es) ride is the critical part. You'll need to use some Scotchbrite or a pencil eraser (followed by contact cleaner ON A RAG, don't spray it) to clean and polish them up so the brushes can make good contact.

Once you have two brushes again that is.

 

Thanks Fitz! I found a pair of brushes for $20 and free shipping! Hopefully I'll be on the road by the end of the week, they should get here by Friday. Already loving this forum and the community behind it!!

 

I'm referring more to the whole copyright issue lol. You know, don't copy in whole or in part lol.

Now if print had an organisation behind it like the RIAA or the MPAA, that wouldn't be going on guaranteed.

/Rant sry heh i'll shut up now.

 

I guess we are breaking the law with the public library's help.
Shuuuuuuuuuuuusssssssssssss. Don't tell anyone.

 

I hope that the brush didn't get broke off when you were taking the cover off (common occurrence) because that would imply that you'll still have a charging problem. As long as the scratches on the rotor don't touch the stator you'll be fine.

 

Is it working?