Help Diagnosing Charging Issue

[TravisT0111]

Hey all, new member here. 07 Street Glide, 89 1200 Sporty ANNNNND a 79 GS750 with a 1000 transplant!!

I'll try to give the basics without a bunch of extra hooplah. Getting battery voltage and nothing higher, no indication of charging. I did the continuity checks across the stator legs, and from the legs to ground, all good there. Stators putting out around 25V AC at idle, up to around 50-60 at higher RPMs, so, I discounted the stator as the issue.

Previous owner who did the 1000 build and install (did a very clean job, no hackery) upgraded from the separate regulator and rectifier units to a modern combo unit. Did the dipde checks, all good. Checked for DC voltage output, was getting nothing. Checked for continuity between battery ground and reg/rec ground, all good. Ordered a replacement unit, getting the same EXACT symptoms. Ive isolated the charging system from the fuse block and related wiring harnesses, so I can discount that.

Here's where I'm confused......wiring diagram for both the 750 and the 1000 are the same (as far as the charging system goes), and of the 3 stator legs, 1 goes straight to rectifier, 1 splits off into 2 and goes to the rec AND the reg, and the 3rd leg goes to the headlight switch.

The rec/reg I installed is a 5 wire......1 being ground, 1 being the DC battery feed, and the other 3 being the AC inputs from the stator. In my install, I ran 3 of the 4 stator wires (all having AC line voltage, so i picked 3 at random) to the rec/reg, and I'm getting nothing on the rec/reg output. Any thoughts? I'm not sure why Suzuki had a stator leg going to the headlight switch, but I have my doubts that the lack of that connection would cause the rec/reg not to produce.

Thanks in advance for any help!!

[Rich82GS750TZ]

Welcome.
Yours is the most common problem that plagues the GS. Most of us have fixed it by:
1) Installing a series type reg/rec like the Shindengen SH775.
2) Eliminate the headlamp loop and run all 3 (yes 3, you should not have 4) stator legs directly to the combo R/R.
3) Clean up all grounds and connect as many as possible to a single point.

Many combo R/R units found at various places are shunt type, and like the original, are not the best for the health of your wiring harness and can cause early stator demise. Series types like the SH775 do not shunt excess voltage, they shut off when peak charging voltage is achieved. At least that's my understanding of it.

Details about all of this linked in my signature. see My Charging System Sorted.

[TravisT0111]

Thanks a lot Rich!!! Just to make sure I'm doing the diagnosis the correct way......I checked rec/reg output both at the battery, as well as checking on the output wire with it DISCONNECTED from the battery. This sound ok?

[Rich82GS750TZ]

While I'm not an electrical expert by any stretch of the imagination, running the bike, I believe you should be seeing 14 VDC + when you measure the voltage output of the R/R while revving the bike to @5K RPM. I think you should probable see in the high 12 to13+ range at idle. Does not matter if the R/R output is connected to the battery or not. This is explained better by people who know more in the Charging system quick test link in my signature.

[Nessism]

I'm not an electrical expert either, but I think the battery needs to be hooked up properly and fully charged in order to perform the DC voltage check. Regarding an AC stator check, the stator needs to be disconnected from the system in order to perform that test. 50-60 VAC is on the weak side, it should be closer to 75 VAC.

Agree on getting an SH775 R/R. I've got a couple of spares if you can't find one otherwise. You can find them on eBay, but be careful, there are lots of counterfeits on the market. Be sure to verify SH775 is printed on the top fin. Polaris, Sea Doo, Can Am, used these a lot.

[TravisT0111]

Thanks guys. Rich, I bumped your 'charging system sorted' thread with a question for Jim, in regards to the leg to ground voltage test.

[Rich82GS750TZ]

Jim won't answer. He no longer posts on the forum. We all benefit from the research an wisdom he contributed over the years and I, for one, miss his presence. Ed, who chimed in above has tested and sold lots of the SH775 R/R units. He also developed the simple diagram posted below to help us dummies with the connections of the SH775.

[alke46]

Thanks guys. Rich, I bumped your 'charging system sorted' thread with a question for Jim, in regards to the leg to ground voltage test.

I'll chime in with what little I know. When my stator went out, I did all the tests that are required and especially I found the leg to ground voltage test which should show 0, mine was showing 31, 28 and I didn't even bother to test the 3rd one because I knew from the 1st 2 that it was done for.

Hope this helps a little and for the record, most of us are using a triumph wiring harness to connect everything. It makes things simpler and can be had for around $10.

[Rich82GS750TZ]

Triumph R/R Connector:

T2500676

http://www.adeptpowersports.com/oem-parts/triumph-link-lead-regulator-t2500676-part.html?gclid=EAIaIQobChMI0sSuyqnx-QIVhdezCh3TCgtaEAQYASABEgL1ovD_BwE