Electrical problem with 85 FJ - Hot rectifier after replacement

[Reborn627]

Good afternoon,

I recently needed to replace the rectifier on my 85 fj1100. The main 30amp fuse would blow even with the key in the off position. After doing some testing I found that the rectifier was bad. I purchased a rectifier from Rick's Motorcycle Electrics and that solved the fuse issue and I was able to run the bike. I've since run into 2 problems. The first, my battery is not charging. This was a slightly unpleasant discovery as I had to push the bike much farther than I'd have liked. No big problem just an annoyance. So, my next step was to replace the regulator, I installed that today but when I opened up the generator I found that the solder points that I had made on the rectifier had vanished. It appears that the rectifier is getting so hot that it is melting the solder. Does this make sense to anybody? Is it simple a matter of an under charged battery or is there something even deeper than the rectifier and regulator. Any help that could be offered would be great. I'm really getting tired of the bike being parked in the driveway. 

Peace,
Ray

[red]

Good afternoon,
I recently needed to replace the rectifier on my 85 fj1100.  I've since run into 2 problems. The first, my battery is not charging.  today when I opened up the generator I found that the solder points that I had made on the rectifier had vanished. It appears that the rectifier is getting so hot that it is melting the solder.   
Peace,
Ray

Ray,

Solder points happen when the soldering work is done with a too cold soldering iron.  The resulting high resistance there makes the joint run hot, even if all else is normal.  Use LA-CO paste flux (it is non-acid, and it's the best).
http://www.laco.com/soldering-fluxes/regular-flux-paste/

Charge the battery with a dedicated battery charger, rather than dumping the work on to the bike electricals.  Check back with an update, for more.

Cheers,
Red

[Reborn627]

Thank you Red. Unfortunately I had no luck with your suggestions . I originally used a medium temp, rosin core, leaded solder and though maybe a higher temp would have been a better choice. I went to radio shack and picked up some silver solder instead. I re-soldered the connections and charge the battery in full. Though the solder lasted a little longer the result was the same. In fact I took a quick run to the gas station to fill up and didn't make it home before I popped the main fuse because of the loss of solder arced out the system. I'm stumped. Short of a full generator replacement I'm not sure what to do. And I also need to decide if it's worth the addition $300 for said generator. Though it runs great, when I'm not having electrical issues, it's no beauty queen. Most of the plastics are damaged and virtually impossible to find at a reasonable cost. I'm not sure if this 30 year old ride is worth the investment that it seems to require. My plan had been to do a streetfighter conversion of some sort but now I'm not so sure. I may have to cut my losses and hope to get $500 for it. Such a drag. I really dig the bike.

Peace,
Ray

[Pat Conlon]

Ray, check your field wire going to your alternator....
http://www.fjowners.com/index.php?topic=8635.msg80450

Search the forum for 'field wire' for lots of discussion....

[Reborn627]

Thanks for the tip Pat but I'm not seeing the symptoms described in those threads. My battery is still not charging and only reads 12.9v max at high rev and I installed a brand new voltage regulator with the new rectifier. Could this field wire still be the problem?

[Pat Conlon]

Still could be....although I thought you had a hot charging condition....you have a NO charging condition...

Dunno why your rectifier is so hot with only 12.9v running through it...

This 12.9 volt number was the measured charging voltage at the battery, correct?
If so, try measuring the voltage directly at the alternator output, then at the input at the regulator.
If you're getting 14-15 volts at the alternator output or regulator input, then it's a voltage loss problem from point A to point B....

My money's on a melted connector (very common when regulators fail) or if everything checks out, a pouched alternator.

[movenon]

That connector can look good on the out side...


George

[Reborn627]

Still could be....although I thought you had a hot charging condition....you have a NO charging condition...

Dunno why your rectifier is so hot with only 12.9v running through it...

This 12.9 volt number was the measured charging voltage at the battery, correct?
If so, try measuring the voltage directly at the alternator output, then at the input at the regulator.
If you're getting 14-15 volts at the alternator output or regulator input, then it's a voltage loss problem from point A to point B....

My money's on a melted connector (very common when regulators fail) or if everything checks out, a pouched alternator.

Ok, here is what I've come up with. I re-soldered the 3 phase connections on the rectifier and got power restored. I checked the field wire connection and it is fried. Because the bike was sitting on the side of the road, thank goodness for power inverters, after re-soldering I made the attempt to ride it home. I didn't quite make it before it arced out again and blew the 30a fuse again. I'll do a bit of research on the field wire issues and see what my solutions are. Chances are I have another fried rectifier, oh how I love throwing $80 in the trash, so I'll have to replace that. This would be a ton easier if I actually knew what I was doing, but google and the forum are my friends. Thanks for your suggestions!

Peace,
Ray

[Yamifj1200]

Your not the only one to have had a problem with the alternator wiring.

If your having a charging problem I'd certainly take a look at these wiring connections. I'm not saying this is your problem but its not a bad thing to check out while your there.

Eric M

[JOMPPA10]

Good afternoon,
I recently needed to replace the rectifier on my 85 fj1100.  I've since run into 2 problems. The first, my battery is not charging.  today when I opened up the generator I found that the solder points that I had made on the rectifier had vanished. It appears that the rectifier is getting so hot that it is melting the solder.   
Peace,
Ray

Ray,

Solder points happen when the soldering work is done with a too cold soldering iron.  The resulting high resistance there makes the joint run hot, even if all else is normal.  Use LA-CO paste flux (it is non-acid, and it's the best).
http://www.laco.com/soldering-fluxes/regular-flux-paste/

Charge the battery with a dedicated battery charger, rather than dumping the work on to the bike electricals.  Check back with an update, for more.

Cheers,
Red

I use silver to make any corrosive joints not cheap but good and good guality shrinkin tubes. sorry my interfierence

[Country Joe]

Your not the only one to have had a problem with the alternator wiring.

If your having a charging problem I'd certainly take a look at these wiring connections. I'm not saying this is your problem but its not a bad thing to check out while your there.

Eric M

On the mark with that photo. I had to replace that connector last week. It didn't look that bad, but still showed signs of melting.   I'm  not finished yet, though.  I'm only getting about 7 volts going back to the alternator, I think I like the idea of installing a relay to feed battery  voltage back to the alternator. If anybody is looking for cheap relays and sockets, check out Parts Express at parts-express.com.

Joe

[Reborn627]

OK, sorry for the long delay. The bike has been parked for quite some time. I replaced the generator. I tested the rectifier that came with the replacement generator (off of an '84) which tested good. Rather than take the chance I swapped the regulator out for the RaceTech Electric that I purchased before. I still was unable to get a charge out of it. So, I load tested the battery and found that it wasn't completely junk but close enough. I'll have to replace the battery. Last of all I'll have to replace the field connector. It is melted. My question is how far back should I clip the wire? Will it be apparent? With it being melted is there something else that I need to check to see if it's failed as well? Man, riding season is more than half over. I gotta get this thing running...and without spending a fortune.

Thanks,
Ray

[Earl Svorks]

 Your melted plug is the scene of the crime. A poor connection there results in a voltage drop across the plug. The generator is working like hell, trying to get the voltage up, what voltage the regulator is reading is diminished by the drop at the plug. The rectifier gets hot from the excessive current being produced.  Cut the plug out and hardwire the connection.Make sure your battery is healthy and fully charged. All connections must be clean and tight (this is VERY important) . When these conditions have been met, then look at running voltage at the battery, post your results,, I'll be watching.

[red]

I'll have to replace the field connector. It is melted. My question is how far back should I clip the wire? Will it be apparent? With it being melted is there something else that I need to check to see if it's failed as well?   Thanks,
Ray

Ray,

http://www.oregonmotorcycleparts.com/connectors.html
http://www.cycleterminal.com/
http://www.easternbeaver.com/Main/Elec__Products/Connectors/connectors.html
http://www.electrosport.com/accessories/connectors-and-wiring.html

At least one of these guys should have the plug that you need, and if not, just get any heavy-duty mated new pair (a male and a female) to make the new connection.  You can use heat-shrink tubing to repair damaged insulation on a wire; it shrinks 25% to 50% of the original size (ask before you buy).  The good stuff has hot-glue coating the inside, so the tubing does not slip later.  These connector shops or a good electronics parts place should have heat-shrink tubing.

All I can say for related problems is to follow the wiring, and look for trouble along the way.

Cheers,
Red

[Reborn627]

Y'all are the best. I'm going to try to get it all taken care of this Saturday. I'll be sure to post my results once completed.

Thanks again!

Peace,
Ray