1985 GL1200 Regulator/Rectifier Testing


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Rednaxs60
Posts: 1338
Joined: Wed Nov 18, 2015 12:44 pm
Location: Victoria, British Columbia, Canada
Motorcycle: 1985 GL1200 LTD, 2008 GL1800

1985 GL1200 Regulator/Rectifier Testing

Post by Rednaxs60 » Fri Dec 01, 2017 12:01 am



I have done two other threads on the electrical system for my '85 LTD and how I have come to understand the system.

Power Junction Thread: viewtopic.php?f=5&t=40650
GL1200 Electrical System Thread: viewtopic.php?f=19&t=40770

I did the test on the OEM regulator from my '85 LTD. For the LTD regulator there should be three yellow wires (from alternator), two red/white wires (go to starter solenoid with a junction in the wiring harness where these wires are joined/bonded to the red wire from the starter solenoid to the ignition switch) , two green wires (ground) and one black wire (12 VDC excitation).

The two ground wires are connected to a single ground wire just after the green wires enter the wiring harness as do the two red/white wires. You will notice only a single red/white wire at the starter solenoid.

I have read the Clymer and OEM service manuals to ensure both are the same.

From the OEM:

Normal direction: Continuity (5 to 40 Ohms)

+ Probe to Yellow (3 wires - done individually) : - Probe to green
+ Probe to Red/White : - Probe to Yellow (3 wires - done individually)

Reverse Direction: No Continuity (over 6,000 Ohms)

+ Probe to Green : - Probe to Yellow (3 wires - done individually)
+ Probe to Yellow (3 wires - done individually) : - Probe to Red/White

From the Clymer:

The Clymer manual test is:

Connect the positive probe to the yellow lead, negative probe to green lead - should be continuity, reverse leads no continuity

Connect positive probe to red/white lead, negative probe to yellow lead - should be continuity. Reverse leads, no continuity.

This is the same as the OEM manual.

The Clymer service manual also has a note that can be misleading. It mentions that this test as specified is for a positive grounded meter. If a negative grounded meter is used the results will the opposite. There is no note like this in the OEM service manual.

It is possible that in reading this note, and that we use negative grounded meters, a person could switch the positive/negative leads, get opposite results and come to the conclusion that the regulator is defective. I submit that if a person uses the Clymer service manual as a guide for testing the regulator, disregard this note.

I have also found a YouTube video on how to check the rectifier diodes:



It is a UK video and mentions connecting the positive lead of the meter to the black wire, this is our green (ground) wire, and the negative to the yellow wires. I used my digital meter as it has a diode function.

I used digital and analogue meters:


I used the analogue to test the regulator because I could not get a reading from the digital meter. I had read about this a few years back. I used the digital meter to check the rectifier diodes as this meter has a diode function.

The regulator I tested was Shindengen SH574A-12 that I took off my bike when I did the external alternator mod:


This regulator wiring is:


OEM regulator wiring - 3 yellow/2 red-white/2 green/1 black. The two red/white wires are joined in the wiring harness into a single wire, as are the two green wires:

The jumper wires I used were red for positive and yellow for negative:


The first test was for continuity of yellow leads (+) to green leads (-):


The reading was 45 Ohms on the 10X scale for all three yellow wires. Reversed the positive/negative leads - no continuity.
The second test was for continuity between red/white leads (+) to yellow leads (-):


The reading was 45 Ohms on the 10X scale for all three yellow wires. Reverse the leads no continuity.

The diode test was done:


The readings were 491/483/491. It is a UK video, and the positive lead to the black wire is a UK ground wire colour. Put the positive lead to the green ground wire of the regulator and the negative to each yellow wire.

Hope this thread is found to be useful.

Cheers


"When you write the story of your life, don't let anyone else hold the pen"

Ernest

kitesurfer805
Posts: 19
Joined: Sun Nov 05, 2017 6:39 pm
Location: Lompoc, Ca
Motorcycle: 1987 Honda Goldwing 1200 Interstate

Re: 1985 GL1200 Regulator/Rectifier Testing

Post by kitesurfer805 » Sat Dec 02, 2017 11:20 am

I am new to motorcycles and recently purchased a 1200 with 86K mile. Just last week I went in and hard wired the stator wires together (got rid of the connector by the battery). While I had the wires apart I tested the stator with engine running and got 75 volts ac on all three wire pair combinations. I then made the hard connection and checked DC voltage out of the Rectifier and was getting 15.75 volts DC which is too high. Checked grounds and all were good so ordered a new Shindengen R/R from ROADSTERCYCLE.COM and am in the process of installing it along with a new tire. I am not complete and don't expect to be able to test until next weekend.

The point I am trying to make here is you should check your stator first and then see what DC voltage is coming out of the rectifier. At least that is how I did my trouble shooting.

User avatar
Rednaxs60
Posts: 1338
Joined: Wed Nov 18, 2015 12:44 pm
Location: Victoria, British Columbia, Canada
Motorcycle: 1985 GL1200 LTD, 2008 GL1800

Re: 1985 GL1200 Regulator/Rectifier Testing

Post by Rednaxs60 » Sat Dec 02, 2017 11:48 am

Does your bike have a dash voltmeter? If it does be interested in the voltage readings after the install of the new R/R.

Roadster Cycle instructions are to install the R/R directly to the battery. I submit it should be hooked up as per the OEM install, with the red - output wire to the red/white wire in the wiring harness. The ground can go to the battery, or use the existing ground wires.

I mention this because Honda designed the electrical system with a "power junction" where the red ignition wire from the starter solenoid is joined with the red/white regulator output wire to the starter solenoid.


The junction is shown in the schematic. This junction "directs" power to where it is needed. Majority to the bike electrical system, and only enough to the battery to top it up and provide a trickle charge afterwards. When you install the R/R directly to the battery you will be bypassing this junction.

The system will work; however, I further submit that you will possibly be putting the battery in a constant overcharge condition by having all the electrical system power requirement at the battery instead of splitting the power requirement at the power junction. Putting the R/R electrical system current of say 20 amps continuous at the battery, the battery has to be in a constant state of overcharge.

I have mentioned in other post(s) that the purpose of the battery and that after starting the bike and is fully charged, it accepts a trickle charge from the electrical system, and the majority of the power produced is used by the electrical system to operate the bike, the power junction allows this. In other words the battery is just another electrical load to the electrical system that the electrical system provides power to.

Had this discussion on another forum with a fellow who installed the Roadster Cycle R/R. He installed as per instructions and always had a lower reading than actual at the dash volt meter. Changed the wiring by connecting the red output wire from the R/R to the wiring harness red/white wire, and the reading on the dash volt meter indicated the correct electrical system voltage.

I have the Roadster Cycle R/R on the shelf, and did have it installed before changing to the external alternator mod.

Just a thought and MHO.

Cheers
"When you write the story of your life, don't let anyone else hold the pen"

Ernest

kitesurfer805
Posts: 19
Joined: Sun Nov 05, 2017 6:39 pm
Location: Lompoc, Ca
Motorcycle: 1987 Honda Goldwing 1200 Interstate

Re: 1985 GL1200 Regulator/Rectifier Testing

Post by kitesurfer805 » Sat Dec 02, 2017 8:18 pm

According to the guy I bought the bike from he had the stator replaced at 45K miles. Whoever did the job rewired it to go directly to the battery so mine was already pretty much done like roadster cycle method. The wires were already cut at the connector so I do not really have a choice. The old installation did have a black wire left intact but when I reconfigure to the roadster cycle method I am not suppose to use the black wire. You can see in the my old configuration that two red wires were connected and run straight to the battery and two ground wires were connected and run straight to the battery. My bike does not have a inline volt meter but I will post what data I do get when I am done. The first 2 photos are of how I got the bike and the 2nd two are of the in progress change out of the R&R. I had to make a bracket to attach the rectifier so that is as far as I have gotten.
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