Multimeter novice

[GSLou]

Thanks for reading!

My 1983 GS550e charging system is not functioning
At idle I have about 12.8v across the battery and it goes down as the RPM goes up.
I checked the stator (AC output >75v) and its good
The RR looks like it's bad. The picture below shows the expected values and the values (yellow) I measured. If you look at the table of my measurements, you might almost believe that you should divide all my numbers by 100 and switch the black(-) and red(+) probes of my multimeter. I don't think I did the measurement wrong or that the mm is in the wrong range, but before I buy a new RR I'd like to be sure.

Any thoughts on how to double check the RR?

[posplayr]

Thanks for reading!

My 1983 GS550e charging system is not functioning
At idle I have about 12.8v across the battery and it goes down as the RPM goes up.
I checked the stator (AC output >75v) and its good
The RR looks like it's bad. The picture below shows the expected values and the values (yellow) I measured. If you look at the table of my measurements, you might almost believe that you should divide all my numbers by 100 and switch the black(-) and red(+) probes of my multimeter. I don't think I did the measurement wrong or that the mm is in the wrong range, but before I buy a new RR I'd like to be sure.

Any thoughts on how to double check the RR?

A http://www.thegsresources.com/_forum...92#post1272192
is a good place to start before taking anything off.

Then use those results to move on to the stator pages.

[robertbarr]

I read some advice on this sub-forum a while back that pretty much sums up how I view this: Forget about any resistance checks / diode checks of a suspect R/R.

If your stator's AC output is good and there's no continuity to ground, there are only two possible causes of incorrect output: the wiring and the R/R. You want to go over any original wiring anyhow, and in the process, install a modern R/R of good reputation.

Since your stator checks OK for AC output (and I'm assuming you've checked the resistance between each leg and ground, and found infinity), you need a modern R/R and an update of the charging system wiring.

[bwringer]

I read some advice on this sub-forum a while back that pretty much sums up how I view this: Forget about any resistance checks / diode checks of a suspect R/R.

If your stator's AC output is good and there's no continuity to ground, there are only two possible causes of incorrect output: the wiring and the R/R. You want to go over any original wiring anyhow, and in the process, install a modern R/R of good reputation.

Since your stator checks OK for AC output (and I'm assuming you've checked the resistance between each leg and ground, and found infinity), you need a modern R/R and an update of the charging system wiring.

Agreed in all respects. The diode checks are completely pointless, and you usually do not get valid results with a multimeter anyway.

As Robert said, it's either wiring and/or your R/R.

[GSLou]

Charging system quickcheck

Posplayr,

Thanks for the link. I truly appreciate your advice. I went through your quick check already. That's how I discovered the faulty charging situation.

Question is whether I'm doing the RR resistance test correctly. I just thought my results looked strange. I didn't (and still don't) know what a failed RR is supposed to look like. I was just surprised that it gave me results that looked like I had the probes mixed up. I don't think I have the probes mixed up. Also, all the numbers would be 100x off.

I think the RR is original so it's probably just best to replace it anyway.

[GSLou]

Robert,

Thanks for the advice. I'm going to follow it and replace the RR and check the rest of the wiring. (When I get the new RR I can check the resistance. If I get the correct readings, I will deem myself fit to handle a multimeter. Keep your fingers crossed)

Happy Holidays!

[BassCliff]

Hi,

For what it's worth, here's the procedure I had posted in the electrical section of my little website:

I performed a diode test on a good spare 6 wire Honda Shindengen r/r unit. These are my results.

Here's what I get on my diode setting:

1) Starting with the (+) lead on the sense wire:

All (-) connections to red output, green ground, and yellow inputs read "+OL".

2) Reversing the leads, putting the (-) lead on the sense wire:

The (+) connection reads:
Red output = +OL
Green ground = ~ 1.5v
All yellow inputs = +OL

3) With the (-) lead on the red output:

The (+) connection reads:
All yellow inputs ~0.54v
Green ground ~0.99v
Black sense +OL

Reversing the above reads +OL on all combinations.

4) With the (+) lead on green (ground) wire and (-) lead on the yellow wires should read ~.54
Should real "+OL" when connections are reversed.

5) Probing between all of the yellow inputs in any combination reads +OL.

Note that the step 3) "all yellow" inputs are the same as the yellow, blue/white, green/white (or red/white) wires connecting from the OE stator.

Also note that in step #3, when testing between the red output and "yellow" input wires, the "~0.54v" readings can vary depending on the r/r model and the multimeter. As long as the readings are consistant, anything between ~0.4v and ~1.0v should indicate a good circuit. If one of the three readings is significantly different from the other two (i.e. two read .4 and the other one reads .7), the the r/r unit would be suspect.

Connections to the sense lead on a Honda r/r are irrelevant for diode tests and are included for information only. Steps #3 and #4 are the critical tests. This same test is valid for 5-wire r/r units, just disregard the "sense" wire information.

Some meters have a diode function. They basically let you know if the diode is passing current in one direction but not the other. Even if the r/r tests good in the passive tests, there's no guarantee that it will function properly under load.


Thank you for your indulgence,

BassCliff

[posplayr]

I read some advice on this sub-forum a while back that pretty much sums up how I view this: Forget about any resistance checks / diode checks of a suspect R/R.

If your stator's AC output is good and there's no continuity to ground, there are only two possible causes of incorrect output: the wiring and the R/R. You want to go over any original wiring anyhow, and in the process, install a modern R/R of good reputation.

Since your stator checks OK for AC output (and I'm assuming you've checked the resistance between each leg and ground, and found infinity), you need a modern R/R and an update of the charging system wiring.

Largely agree, I seldom feel compelled to do the diode tests on an R/R and almost as a first step make sure that all the connections to the R/R are good. But as has been discussed at length here, the stator tests are not conclusive (see revised tests Phase B) unless done under load and even then the Unit under Test (UUT) can be changing based on the thermal heating of the stator and the break down of the insulation of the stator. So caution on assuming you have a good stator is always warranted lest you don't care that much about doing a stator R/R.

In the Quick Test I'm always looking for evidence of any charging. If that is the case then I assume the R/R is probably OK and then focus on connections and if that fails to improve things then the stator becomes the primary focus.

There are four elements to the charging system:
a.) Stator (best tested under load, you don't usually get FALSE failed tests but you can quite often get FALSE GOOD tests) bad about 50-60% of the time
b.) R/R (Don't usually fail unless it is obviously burned or open as can be detected in the Diode tests) bad about 10% of the time
c.) Battery (need to do a basic load test like in the QUICK TEST)
d.) Wiring and connections (best done under load as prescribed in the REVISED Stator tests Phase A. Critically Bad about 30-40% of the time of just bad about 60-70% of the time.

[posplayr]

Posplayr,

Thanks for the link. I truly appreciate your advice. I went through your quick check already. That's how I discovered the faulty charging situation.

Question is whether I'm doing the RR resistance test correctly. I just thought my results looked strange. I didn't (and still don't) know what a failed RR is supposed to look like. I was just surprised that it gave me results that looked like I had the probes mixed up. I don't think I have the probes mixed up. Also, all the numbers would be 100x off.

I think the RR is original so it's probably just best to replace it anyway.

I was not clear you have done the Quick test as you did not post the results. Without knowing what the voltages were at each step, I would be guessing to much to offer a comment.

As discussed the directions for doing the diode tests are pretty clear. You have to realize that those tests are mostly positive confirmations and not necessarily positively conclusive the R/R is good.

[GSLou]

RR results and follow up question?

Here are the quick test results:

1. Engine off: 12V. Not enough to start the bike on a cold day in CT, so I charge it up to 12.9 and continued. (The failure to start is want prompted all this testing.)
2. Idle: 12.8 - 13 ish
3. 2500 rpm 12.5 ish
4. 5000 rpm 12.3 ish

I then checked the RR and Stator as described in the shop manual.

So based on the advice here, I'm going to replace the RR and clean/check all the wiring and see if that fixes things.

I spoke with the PO last night. He told me the RR failed in 1990 on a ride and he replaced. So, what RR should I put in? I followed the link in the stator papers and they have one that looks like the stock RR. Is this the best option?

Again, thanks for for reading!

[cowboyup3371]

Tight valves will also cause hard starting in the winter. When was the last time you adjusted them?

[GSLou]

Valves

Thanks for the suggestion Cowboy,

The valves were adjusted in the spring by the PO, who is a good friend. I'm confident it's not the valves, but thanks for the input. It's certainly good to think about all the possible sources of my problem before I buy any parts.

[posplayr]

Here are the quick test results:

1. Engine off: 12V. Not enough to start the bike on a cold day in CT, so I charge it up to 12.9 and continued. (The failure to start is want prompted all this testing.)
2. Idle: 12.8 - 13 ish
3. 2500 rpm 12.5 ish
4. 5000 rpm 12.3 ish

I then checked the RR and Stator as described in the shop manual.

So based on the advice here, I'm going to replace the RR and clean/check all the wiring and see if that fixes things.

I spoke with the PO last night. He told me the RR failed in 1990 on a ride and he replaced. So, what RR should I put in? I followed the link in the stator papers and they have one that looks like the stock RR. Is this the best option?

Again, thanks for for reading!

Quick Test Steps:

1.) key off................Normal 12.7 volts-12.9 volts

2.) key on (but not cranking with lights for 10 sec).....Normal 12.2-12.5 volts

3.) at idle (1500 rpm).....12.6volts - 13.2volts

4.) at 2500 rpm 13.5 -14.0 volts

5.) at 5000 rpm.....14.0 -15.0 volts

6.) key off.....slightly higher than measurements # 1 (12.8-13.0 v)

You still have not specified all of the test points(they are all required to apply the diagnosis listed in the tests). But the fact that you appear to idle at 13.0V means you are rectifying even if not regulating and I would suspect either very poor connections or your stator is going out. First course of action is clean the connections then redo the quick test measurements. It could also be a bad battery it is not really possible to diagnose any better than that based on what you listed. List all 6 steps.

[GSLou]

quick test numbers

Posplayr

1. Key off: 12.5v
2. Key on after 10s: 11.9v
3. Idle: 13.2v
4. 2500 rpm: 12.4v
5. 5000 rpm: 12.2v
6. Key off: 12.5v

Thoughts?

[posplayr]

Posplayr

1. Key off: 12.5v
2. Key on after 10s: 11.9v
3. Idle: 13.2v
4. 2500 rpm: 12.4v
5. 5000 rpm: 12.2v
6. Key off: 12.5v

Thoughts?

You are charging so check the voltage drops across the connections as indicated in revised phase a. Your voltage drops are probably large indicating bad connections
You went from 11.9v to over 13v, that is charging so r/r is possibly ok