P
Phaseman
Guest
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 will upload and add pics shortly.
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.
Any thoughts or recommendations are appreciated!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???1st pass, I only had continuity through 2 of the 3 wires.
2nd pass in the other direction. same exact readings.
I will upload and add pics shortly.
Last edited:
