Charging Issues (so far the rectifier seems to be the culprit).

[Phaseman]

Hello clever GS'ers,

My 78' GS100E has ceased to charge itself.
Before I explain where I am at with it let me give you this little nugget to keep in back of your mind. Shortly before this charging issue surfaced, I was cruising down the road on a cold morning (38deg or so). About 2 blocks away from my house and before the bike had fully warmed up, I heard a mild "pop" and the bike shut down. I got her turned around for a walk back to the house when I thought, "Hmmm, no cluster lights", I stopped and pulled off the side panel and discovered that I had blown the 15a main fuse.

Fortunately I had an extra and plunked it in, bike fired right up. I rode around the next couple of days with no trouble, then on the third day while running down the highway, pop, at 75 in the fast lane, then no power again. Being rather retentive about my bad luck, I had already replaced the spare, popped in another and away I rode. The 2nd fuse was however replaced with a 20a fuse and I had no trouble for a few weeks of regular riding.

That brings me to the point that it began to fail in charging. I came home one night with badly dimming headlamp and after that I started throwing it on the maintenance charger every night when I parked it. The problem got worse and worse until it just stopped charging altogether.

I got myself a fresh battery and started going through the system per the maintenance manual troubleshooting steps.

1st step) pop out headlamp fuse and hook up a voltmeter to the pos and neg. Start bike and take her up to 5 Grand. If V goes up to between 14-15 volts you're ok...
mine dropped like a rock to 11v.

2nd step) Check rectifier for one way conductivity...

I pulled off the rubber boot to expose the rectifier connectors to find an ugly clump of bullet connectors that looked like they had been through 35 years of hell and spark damage. I thought! That could be it! I had to cut the wires as they would no longer pull apart. I actually checked continuity through each of those connectors thinking that may have been the only prob. As ugly as they were, the all allowed current to pass through. So, on with the rectifier test.

With Neg probe to grd on the rectifier I was supposed to have continuity through yellow, white/blue and white/red...

With pos probe to grd, I was supposed to have no continuity through the same wires.

Here is what I got instead...
1st pass, I only had continuity through 2 of the 3 wires.
2nd pass in the other direction. same exact readings.

So basically FUBAR, I think I need a new rectifier. Isthat your take? Also and recommendations on where to buy. Best price I have found online for new is 182.00. YIKES! You guys think I should try to find a used one that passes the test for a few bucks or what???

Any thoughts or recommendations are appreciated!

I will upload and add pics shortly.

[BassCliff]

Hi,

Does your bike have a separate rectifier and regulator? Even if it does, duaneage might have a good used tested Honda upgrade r/r (combo) unit that will work.

Have you tested your stator yet?


Thank you for your indulgence,

BassCliff

[Nessism]

For one thing, your bike has a separate Regulator and Rectifier. Most later GS bikes, and most bikes in general, have a combined R/R unit. There are tons of options, as there are tons of threads here in the archives describing those options. Do a search and you will find lots of recommendations. If for some reason you want to stick to the stock parts, I think I have a stock regulator and rectifier from one of my old GS1000's you can have for (dirt) cheap. Drop me a PM if you want to discuss.

[blowerbike]

one option would be converting it to a reg/rect combo...
either OEM style or one of duanes honda RR jobs.
ive had GS's pop the main fuse from having a stator short out.

[Phaseman]

Thanks for the quick feedback!

Thanks Guys!

BassCliff Hi -
Does your bike have a separate rectifier and regulator? Even if it does, duaneage might have a good used tested Honda upgrade r/r (combo) unit that will work.
Cool, though I recognize the value of a good upgrade, I am a bit skiddish when it comes to moving away from the tech manual that I have. Wrenching doesn't scare me much but the electricle stuff spooks me, not much experience.

By far my biggest chalenge to date was the carb rebuild last year. Thank God for those tutorials you have up, saved my bacon (and my $$$) carbs are running great now.

Have you tested your stator yet?
No.... SCARED!

Thank you for your indulgence,
No, Thank you sir!

BassCliff

Nessism -For one thing, your bike has a separate Regulator and Rectifier. Most later GS bikes, and most bikes in general, have a combined R/R unit. There are tons of options, as there are tons of threads here in the archives describing those options. Do a search and you will find lots of recommendations. If for some reason you want to stick to the stock parts, I think I have a stock regulator and rectifier from one of my old GS1000's you can have for (dirt) cheap. Drop me a PM if you want to discuss.
Thanks Ness, you have helped me greatly in the past! Sent you a PM.

blowerbike -one option would be converting it to a reg/rect combo...
either OEM style or one of duanes honda RR jobs.
ive had GS's pop the main fuse from having a stator short out.
Sounds like good advice to me Blowerbike, see above for my fears!

[Phaseman]

PS I added a couple of pics.

I added pics to the opening post if you wanna see em'!

[chef1366]

I have a rectifier and a R/R.
Pick your poison.

[duaneage]

Or go with one that lasts a really long time

http://www.thegsresources.com/_forum/showthread.php?t=148739

[Phaseman]

Install question?

Hello all,
I just received my R&R unit from duaneage today. I am going to PM him with my Q's but thought that maybe someone here would be able to answer these questions as well.

1) The combo unit that duaneage sent me has three wires that are all the same color, yellow. I presume that this means that it does not matter which alternator wire that each connects to. My original Rectifier was connected by three color specific wires.??

2)The new combo unit has a black wire coming out that is split for 2 connections, one says to go to the orange wire on the fuse box and the other is to go to .... Well this is where I am confused. It looks like they are supposed to connect at basically the same place, on the orange wire between the Fuse Box and the Brake light switch. Am I reading this wrong?

Here is the wiring diagram I am looking at. http://img.photobucket.com/albums/v7...nections-1.jpg

[BassCliff]

Hi,

Yes, the three yellow wires can connect to the stator output wires in any order.

The black wire is the "sense" wire. That's why you must connect it to a switched 12v source in the harness. It monitors the voltage in the system so the regulator knows how much voltage to output. The tail light is about the closest connection, but there are other places. What you are doing with that "double" connector is placing the sense wire in the path of the tail light wire. You see, one of those split connectors is male and the other is female. Disconnect the connector to the tail light at the brake light switch then re-connect it using the "split" (male/female) connector on the wire from the r/r unit, an "inline" connection.


Thank you for your indulgence,

BassCliff

[duaneage]

I like to use the orange wire that feeds the rear brake light switch because it's right there and always the same. It comes on with the key.

[Phaseman]

Great Set up duaneage

Thanks guys,
R&R unit from duaneage is installed and giving me a good solid 14.8v.

With that handled I now have a new thread going on. Cyls# 2and 3 cutting in and out. Seems like these troubles always come up overlapping just to confuse matters.

The other tech thread is "One Cylinder from each Coil Shutting Down!?"