From what I've read the early 80s Suzukis were known for charging system problems. Suzuki seems to have skimped in this area by using a smaller gauge wiring, a lack of relays and other little details which, in my case specifically, results in not enough voltage getting to the battery to even recharge it now.
I experienced this in the first 20 minutes of ownership when the battery died completely at highway speeds and it shut down. After a $300 mechanics fee and travel/towing logistics they handed me a melted connector and said I'd need to replace the stator and regulator.
Here is that process (Part 1)
After getting it back from the shop (I really had no choice, I was in Northern Connecticut) I set about replacing the charging system. I measured the output voltage at the battery and it was 12.7 at 4K rpms. Not good. I ordered a stator and regulator from Ricks on ebay for about $170 total. The stator is located under the crankcase cover on the left and is cooled by oil so get the drain pan ready.
The regulator is located under the left plastic cover and is secured with two bolts and a ground only. The regualtor is a fairly straight forward replacement and the one I ordered even had the stock wiring colors making it an easy swap using the Suzuki wiring diagram in the repair manual. Have I mentioned the repair manual yet? If you dont have one, get one. I was able to troubleshoot some incorrect wiring and redo almost the entire charging system with it.
All fairly straight forward. The charging system is simple really. The stator makes electricity, passes it to the regulator/rectifier which passes it to the battery. One just needs to make sure they are working properly and you have good wiring/connectors between. The only hang ups I had were getting the gears aligned again when re-installing and feeding the wire to the regulator. Patience solved the first problem and loosening the bolts covering the front sprocket helped on the second. The old stator looked worn, I guess, as it should after 30 years of work.
I read several blogs that state when replacing the stator you should replace the regulator as well because the new unit tends to "blow" the old unit. I also replaced the battery while I was at it and redid most of the connections using clip connectors or bullet connectors. Sealed everything up and checked the voltage again. 13V!
Well, OK not great but good enough to get me on the road.
While sitting at a red my GS1100e suddenly died. Totally and completely. Couldn't even pop start it. Luckily I was only about 2 miles from home and was able to walk it back. I chalk this up to only getting 13 volts and the GS running totally from the battery and the battery eventually totally draining.
Back in to the wiring. Upon inspection I found some melted wires and a few bad connections further up the main harness. To whoever worked on this before I'd like to have a word. So I replaced those and also found a wire that had been spliced incorrectly leading me to attach the regulator to the wrong spot. I cleaned all this up and got it as close to spec as possible with one exception: I ran the positive from the regulator directly to the battery. I'm assuming this is not correct as it should probably go through the fuse box first but after I did this I got 14.8 volts at the battery! Wow, that's what I wanted to see! So I'll find why the wiring/fuses box is causing a problem but left it at that for now.
Side note, I also discovered the headlight runs off AC directly from the stator and this was wired wrong also. Each stator wire puts out about 50 watts of AC before the regulator converts it to DC and drops it to 14-15 volts. I fixed that, blew the headlight, and ordered a new one. Will update this post once I work out those little issues but for now the electrical system is back on track.
90% of the charging system is new now and works well. Ultimately I'd like to replace the main wiring harness with a newer model that has larger gauge wiring and some relays, especially for my USB charger.