RR neg to battery neg mod question

[posplayr]

Is this the original problem?

I did check the volts with the bike running at various rpms (2,500 - 5,000) and I was only getting slightly more than 13 volts. In the stator papers it said 13.5 to 14.8 was the normal.
 

Did you ever check the voltage difference between the R/R negative and the battery negative
at Idle? What is it
at 5000 RPM ? What is it?

Did you ever check the voltage difference between the R/R plus output and the battery positive
at Idle? What is it
at 5000 RPM ? What is it?

All of these measurements should be less than 0.5v preferably less than 0.25 volts. If not then you still have connection issues that won't be fixed by replacing the stator or R/R. If you want to fix you bike without changing these components you will have to make sure your connections are right and run that to ground first. If that doesn't fix the problem then start looking to stator and R/R. Get a VOM!!

Posplayr

[bryan]

Yes, that was the original problem. Per the stator papers, I did the following steps. Will this test what you're describing:

"Let the engine idle, and connect the black multimeter lead to the battery(+). Connect the red multimeter lead to the RED output wire of the RR. Leave the RR connected to the bike. Check the reading on the meter. Leave the engine idling!"

"Connect the red multimeter lead up to the battery's negative pole (-) Connect the black multimeter lead up to the negative output of the RR (BLACK/WHITE), but leave the RR connected up to its leads on the bike. If you can't find a negative output wire, then the casing of the RR is normally the negative lead to the frame. Check the reading on the meter. Leave the engine idling !"

Those checked out, but I didn't check these at the various RPMs you mention.

Man, where else on earth could you get free advice and patience like this :-D

[posplayr]

Trying to keep it simple

That is fine; So what voltages did you get at idle and what was it after you reved the engine to 5000 RPM? (same electrical connections).

That is all I was asking 8-[


Did you already tear down the bike and remove the stator and R/R?

As mentioned before:

The stator papers are not incorrect but they don't really do a very good job of driving home the point that the small resistances (10 amps into 0.1 ohms generating close to a volt) can cause a failure to charge adequately. The only way to really tell because of the low resistance is to increase the current so that the voltage drop is most observable. That occurs at the higher RPM.

Thus simple modification to the Stator Papers is to insure that voltage drops are low (<0.25 volts ideal) at 5000 RPM (<0.5 volts OK).

If you only have 13.0 output that may not be enough but the charging system is definitely putting out something else you would be draining the battery at about 12.5 volts or lower assuming it is about 12.8v with key off. So the stator is working some and the R/R at least is not over charging. By ruling out your connections you can either fix the problem or move on.

Just trying to ensure that the positive side does not have too much of a drop as previously stated.

Posplayr

[bryan]

I only checked at idle it was .2 or less (don't remember exact), so I moved on to "Test Phase B."

I'll check at 5,000 RPM tomorrow night and post again.

[bryan]

Did you already tear down the bike and remove the stator and R/R?

Oh and no, I haven't removed the components yet.

I'm definitely getting some charge, but after a long'ish ride my battery light will come on and when I'm done it will have dropped to 12.3 or so. After two or three rides if I don't put it on a charger it will eventually not have enough to turn over the bike.

I looked at other connections outside of the charging system and things SEEMED fine, but is it possible for a bad connection outside of the charging system to cause these symptoms?

I took the battery to get tested at Advanced Auto parts and it is SUPPOSEDLY okay in terms of charging and cold cranking amps.

[posplayr]

Tests

OK back to your first question of the nite:

Any way to test used Stators/RRs at salvage yard?

This is probably a dumb question, but is there anyway to test used stators or RRs when their off a bike?

The only test in Section B or C that involves the bike running or could ONLY be done with the parts installed is the last test in part B. The ohm meter tests in B and the entire Part C could be done in the junk yard.

Question is the only thing you should buy at the junk yard is the stator "if it is bad". If you get a R/R get duaneage's Honda unit for only $40 delivered and it solves several problems as well.

As I have reread your descriptions, assuming that your 5000 RPM voltage difference(battery to R/R) reading is low you might be looking at a stator. If you can charge the battery and it takes a charge, but ridding around drains it then basically you are not getting enough out. The R/R would probably fail to regulate and over boil the battery not cause under charging. It doesn't really stop charging unless it were to short and smoke all of your wiring.

Get the voltages and confirm wiring but be prepared for a stator. I have a spare 1981 GS750 stator (old).

Posplayr

[bryan]

Update on charging issue

Bearing in mind I really don't know what these numbers mean, according to the flow chart it looks like I have a bad stator. Here are the steps followed by my readings in red:

"Switch the multimeter to DC Volts. Switch the range to 20 or 50 V. Connect the multimeter leads to the battery terminals. Start and rev the engine up to 2500 rpm. Check the battery-voltage" 12.5'ish at 2,500 RPM; 13'ish at 4,000

"Let the engine idle, and connect the black multimeter lead to the battery(+). Connect the red multimeter lead to the RED output wire of the RR. Leave the RR connected to the bike. Check the reading on the meter. Leave the engine idling!"
Idle -.25; 5,000 RPM .13

"Connect the red multimeter lead up to the battery's negative pole (-) Connect the black multimeter lead up to the negative output of the RR (BLACK/WHITE), but leave the RR connected up to its leads on the bike. If you can't find a negative output wire, then the casing of the RR is normally the negative lead to the frame. Check the reading on the meter. Leave the engine idling" 0.00 - Assuming this is because of the negative RR to negative battery terminal mod I did?

"Stop the engine. Disconnect the wires emerging from the stator. Switch the multimeter to Ohms, the lowest range on the meter. Connect the multimeter leads BETWEEN two of the three yellow wires. Check the reading on the meter. Switch one of the multimeter leads to another of the three wires and check the reading again..."
Green/White and Blue/White - No Reading (1 .)
Green/White and Yellow - 1.5
Blue/White and Yello - No reading (1 .)
Green/White and Blue/White - No reading (1 .)

Is no reading odd? Clueless. But it seems all signs point to bad stator.

[duaneage]

Is no reading odd? Clueless. But it seems all signs point to bad stator.




A bad RR leads to a damaged stator

Here are a couple of points on the subject of charging systems,


The purpose of the RR is to power the bike, not just charge the battery. Yes, the battery is kept charged but the RR is tasked with powering the bike, at cruising speed the battery does not power the bike. You can run with no battery and it would still work, since the electrical system provides the juice. In fact that is a good test for the bike, disconnect the battery - lead while the engine is running and see what happens. A bad electrical system will stop the engine immediately/

THe RR case is not grounded. Attaching a ground wire to it won't do much except maybe shield it or something.

The best ground connection on your bike is the frame. In fact, the other devices like lights and horns, starters, coils, etc are connected to the frame at some point. Make a new ground wire from the battery to the frame, then run a SHORT ground wire from the RR to the frame. Keep ground wires from devices like an RR as short as you can and use the frame,

Establishing a great connection from RR to battery and back sounds like a plan but ignores the rest of the bike. If the connection from the battery to the frame is questionable then what good is a battery charger that can't properly power the bike?

Everyone hates bullet connectors, and I agree the connections on these bikes are less than ideal. But new bullet connectors offer as much contact area as a spade terminal and test out just as good as a spade does. The problem is not so much what type of connector it is how old. New connectors are not made of brass, they are much better designed than what they had 30 years ago.
Just my .02 on the subject.

I offer Honda RR kits for Suzuki bikes, several dozen have been shipped already, and for 40 dollars delivered it's the best insurance against RR failure there is. The Honda beats OEM suzuki hands down, and the aftermarket RR's are about half the size of the Honda. The Honda also has a voltage sense that measures the bike voltage and adjusts accordingly. By looking at the bike voltage, not just what leaves the RR, it can compensate for load, battery level, resistance, whatever.

PM me if your interested in one, I ship the very next day

[posplayr]

Well the connections appear OK

But there are still some inconsistencies in your results.

a.) Did you really mean to make the second voltage positive?? That would mean that the battery is draining at 5000 RPM. The negative number at idle means the charging system is supplying current to the motor cycle. A plus sign means current is moving to the R/R output. The bike has no way of producing power so it must be coming from the battery. Check that sign again.
Idle -.25; 5,000 RPM .13

b.) 0.1 ohms is not very much to generate 1 volt as said before. Measure the voltage dont assume. Even after putting in direct ground to both negative side of the battery and the chassis I still have 0.30 v difference.

0.00 - Assuming this is because of the negative RR to negative battery terminal mod I did?



c.) What is the lowest range reading on your Multi meter when it read ohms? (short the leads and see how it reads)
I just checked a GS750 stator and there should be about 0.7 ohms between stator legs. No reading seems to indicate low resistance but the G/W to Y leg seems to be high if we are to believe you are measuring right. You should get the same 0.7-0.8 ohms between any two legs. The high one suggests that that one leg of the stator may be bad. However I dont know how it effects only one measurement pair(two should be bad)? Recheck what you are going?
Green/White and Blue/White - No Reading (1 .)
Green/White and Yellow - 1.5
Blue/White and Yellow - No reading (1 .)
Green/White and Blue/White - No reading (1 .)

Recheck and see if we are to believe these numbers mentioned above. If we are to I guess i would order the Honda unit, install it and see if it corrects the problem,. The worst thing is then you have to replace the stator but the Honda unit is still at $40 is a cheap upgrade.

Posplayr

[bryan]

Thanks, guy. I'm learning a little something here. Trying to soak in as much as I can. I'll triple check all of the readings again. And let you know what I find.

[posplayr]

You will feel like an old

pro once you get it fixed. \\/

Posplayr

[posplayr]

duaneage

THe RR case is not grounded. Attaching a ground wire to it won't do much except maybe shield it or something.

As I mentioned before I think there was an improvement in regulation when I tied the R/R neg to the case v.s. not doing it. I probably did this with an alagator clip. It was back in Dec so I will have to repeat when I swap out the Honda R/R and will report back.

I'm pretty sure I did this all before adding the big copper pipe grounds.

Agree that there also needs to be good chassis ground to the battery negative.

Posplayr

[duaneage]

His stator is toast. Looks like one leg.

To get an accurate reading of the stator windings the ohm meter must be set to zero. Digital meters, at least expensive ones, have a zero button you press while holding the leads tips together. This eliminates the little bit of resistance in the leads and gives an accurate reading. Needle meters had a control that let you zero the meter the same way.

Looks like one leg of the stator is a bit higher than the other, classic example of a RR that took a stator with it. The strange voltage readings are a combination of bad stator and bad RR.

Here is a wiring diagram, this may help a bit



Notice how all three come together and then the result gets adjusted ( this is for the Honda RR but with the exception of the sense wire the Suzuki is similar). You need all three legs of the stator to work or it limps along at around 2/3 efficiency. That is barely enough to run the bike and not nearly enough to charge the battery as well.

One interesting thing is the ground is regulated, not the + output. Japanese voltage regulation is sometimes done on the grounds not the +

Sony televisions were this way for years, they used regulation on the ground side not the hot. I always thought it strange, but then again voltage actually flows from - to +, not the other way around.

This is why you have to pay attention to the ground connections on a motorbike, it's essential.

[bryan]

If the connection from the battery to the frame is questionable then what good is a battery charger that can't properly power the bike?

I checked the main ground and it was clean, so I'm pretty sure that isn't it. I also polished it up with a little steel wool for good measure.

What is the lowest range reading on your Multi meter when it read ohms? (short the leads and see how it reads)

it goes from 2000k down to 200. When I short the leads at 200 it reads .7

Measure the voltage dont assume.

This was what it read on the meter. I just meant I assumed that 0.00 reading had to due with me putting the ground mod on.

Can't wait to take a long, LONG ride when I get this all sorted out!

[posplayr]

Remote debugging

Looks like one leg of the stator is a bit higher than the other, classic example of a RR that took a stator with it. The strange voltage readings are a combination of bad stator and bad RR.

See my comment. If you are always measuring the resistance between (thru) two legs how does just one get high? Two should be high. But maybe he did not zero out the meter and somehow we actually have two high and one low ??? Or there are actually one short dragging the two measurements down so the high one is the good one??? Dunno

Bottom Line : all three comparisons need to be close to the same.

That positive voltage flow to the R/R was a pretty clear indication of bad R/R (again if we believe the measurements).

Unless he can get a good read on the stator I think I would just try the Honda R/R and see if it fixed the problem. If the R/R is wacky, it suggests that the charging is not "that" bad and maybe he could put off the stator replacement for a while.

He would need to be careful and make sure that with the new R/R everything was OK and not run it on a bad stator (and then take out the good new R/R).

Posplayr