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Simplified diagram showing how current flows from the R/R(+) through the red wire and returns back through various Black/White ground returns. The green wires are the two recommended additions to improve current flow back to the R/R(-) . If you remove either A: or B: green wires you should be able to visualize how the current gets back to R/R(-).
Addition of A: makes the R/R be connected directly across the battery.
Addition of B: allows frame currenst to flow back to the R/R(-) without going through the harnes B/W or past the battery. Without current flow is less direct and creates additional voltage drops that can affect charging.
Is your R/R grounded to your frame?
This has become a bit of a running joke since I started the thread below.
Edit: I'm ignoring any responses bakalorz because of his inconsiderate responses, inappropriate comments, sophomoric and circular logic all apparently due to a predisposition for elevating his own self esteem by proving himself right. He is not worth my time. He used up most of my tolerance for him a along time ago. The last posts in that thread is typical of such a unsavory sort.
A quote from Bakalorz
Oh well, I guess he is not even very good a making veiled comments. This is a guy he ran over the maximum length on about 3 full posts to dissect, critique and dismiss everything I wrote all to conclude that retaining the stock configuration and adding a ground wire as he apparently had suggested earlier was OK.
Gee whiz you would have though if I got some much wrong in the analysis that it is a miracle that I got an answer that bakaloz agreed to in the end. What are the odds of having some many counteracting "mistakes" and still come up with the right answer? I must have gotten very lucky as the probability of getting every other element wrong and still coming up with the right answer is astronomic. On the other hand Bakaorz could be an analytic wannabe and can only demonstrate his prowess in an unmoderated non technical form such as this.
This edit is intended as a warning, because my analysis on electrical stuff sure seems to collect flys. Balalozor is the biggest one and I'm sure he will show up here as well. I will ignore him
I was just looking for some pics for Cliff and found this pic that I would like to post in no uncertain terms as a warning.
This is a picture of the battery area of my newly acquired 1981 GS750EX. I bought it 1/20/2007 and this picture according to my camera was taken on 1/24/2007 4 days later. At the time the battery was weak and 1/2 full of electrolyte. The PO had recommended I change the battery so as I was doing this I was checking out the charging system.
So you know what you are looking at there are two OEM ring lugs for chassis (frame) ground that have been heated to the point that 95% of the insulation had burnt off or had curled away from the wire. This condition existed for the entire current path from one ring lug, to the point at which this wire connects to the black/white ground wires in the harness and then back to the other ring lug.
This wire was carrying a whole lot of current 30+ amps to fry the insulation off of a wire such as it did. Remember the charging system is only supposed to carry about 12 amp total and there is only a 15 amp fuse in the fuse box for the whole system. The only part of the harness that was charred were those parts that had direct exposure to the connector crimp in the harness which tied the two ring lug wires to the rest of the grounds in the harness. In other words the current was not coming from the harness. If it had of been it would have blown the 15 amp fuse which would not have allowed the current to flow in the first place. So clearly we are looking at a situation where very high ground current (>>+15 amps) is flowing between the two ring lugs.
The only other evidence of heat damage I could find were in the three stator wire connections to the R/R. These had obviously been hot, as the wire was stiff and the insulation distorted. I can't remember now for sure if there were OEM or had been changed, but my guess is it was all stock.
For reference these two ring lugs are mounted to :
1.) The front mounting bolt of the battery box (under the rubber washer spacer) to establish a frame ground.
2.) The solenoid on the side mounting plate to tie that rubber mounted plate to the frame ground.
As far as I can tell the changing system, stator, R/R and the harness was all OEM and stock including the single stator wire that ran to the headlamp switch.
I'm pretty sure I remember other members here describing a similar condition.
So here is what I did.
1.) Replaced the connections between the stator and the R/R removing the leg going to the headlamp switch.
2.) I replaced the wires and ground lugs attached to the harness.
3.) Made a heat sink from copper tubing to be mounted under the R/R.
4.) I acid dipped and flowed solder into all of the fuse box crimps.
5.) Added a ring lug to the R/R ground frame mounting that connection.
6.) Made a ground wire to strap directly from the R/R frame mounted ground to the Battery (-)
7.) Made a ground wire to strap directly from the solenoid to the R/R frame mounted ground.
8.) I DID NOT CHANGE THE R/R and I DID NOT CHANGE THE STATOR.
Guess what complete charging function was restored with no more than 0.25V between R/R (+) and Battery (+) as well las between R/R(-) and Battery(-) as measured at 4000 RPM. The Battery voltage at 4000 RPM when to about 14.5 volts.
I verified this with a second OEM R/R from a parts bike with virtually identical results. Finally rather than temp fate, I swapped out the stator for an Electrosport model as the insulation is old and prone to shorting. There seemed to be a drop in the A/C output voltage under no load testing, but there was no significant change to the overall system charging function as I recall.
Here is the heat sink that is under the R/R. I used the EMI gasket material with heat sink grease to create a good thermal ground to the frame by bolting the curved sections to the frame section directly above the R/R.
EDIT: I was a little inconsistent and changed the ground some; Here is a final configuration:
By picking one of the R/R mounting bolts as the single point ground point, the R/R(-) wire can be very short, the mounting plate is automatically grounded and all of the return current wires can be tied securely together at a single point. Here are the connections
Here is a matching picture on a GS750EX, it will work well for most all E's at least. The layout may be a little different on the G's and L's but the ideas will be the same.
So what is the moral of this story?
There is a FUNDAMENTAL and LATENT design defect in the overall GS charging system, that allows perfectly functioning components to smoke the harness even with a properly functioning fuse box. I call it a design defect because overall the system was subjected to connection degradation alone and it caused the destructive behavior without having any defective (i.e. broken) parts.
My assessment of what happened in that:
a.) high current flowed from ring lug to ring lug.
b.) The current did not pass through the battery as the battery is fused at the + terminal
c.) The ground current is related to a stator current flows.
My assessment of how it happened is incomplete:
a.) We know that there is nothing preventing or limiting current flows in the stator or inside of the R/R.
b.) There are only two possibilities for the direction of the ground flow which are:
i.) the R/R ground sourced current.
This would be very unusual unless the one of the stator connections were so bad that there was an alternate lower signal path to complete the 3 phase stator current paths.
ii.) The R/R ground sunk current.
This is the normal operation, but that current flow is not from the GS load.
The above analysis supposes that the schematics provided in the Suzuki manual are connect, however since we really don't know what is inside of the OEM R/R's there could be something else going on.
The discovery of these burnt wires has spurred me to try and determine a mechanism for the current flow. The best I can figure is to make sure that your grounds are good and possibly get away from the OEM R/R. I'm moving to FET based versions as then are both newer and more efficient. With the FET design the FET control is separated from the power device, and so this is fundamentally different to the other shunt regulator devices from a circuit topology standpoint. This is maybe additional benefit of the FET devices.
Pos
Addition of A: makes the R/R be connected directly across the battery.
Addition of B: allows frame currenst to flow back to the R/R(-) without going through the harnes B/W or past the battery. Without current flow is less direct and creates additional voltage drops that can affect charging.
Is your R/R grounded to your frame?
This has become a bit of a running joke since I started the thread below.
.png)
Edit: I'm ignoring any responses bakalorz because of his inconsiderate responses, inappropriate comments, sophomoric and circular logic all apparently due to a predisposition for elevating his own self esteem by proving himself right. He is not worth my time. He used up most of my tolerance for him a along time ago. The last posts in that thread is typical of such a unsavory sort.
A quote from Bakalorz
I don't want to be rude, but until you account for that, all your analysis isn't worth a bucket of warm spit.
Gee whiz you would have though if I got some much wrong in the analysis that it is a miracle that I got an answer that bakaloz agreed to in the end. What are the odds of having some many counteracting "mistakes" and still come up with the right answer? I must have gotten very lucky as the probability of getting every other element wrong and still coming up with the right answer is astronomic. On the other hand Bakaorz could be an analytic wannabe and can only demonstrate his prowess in an unmoderated non technical form such as this.
This edit is intended as a warning, because my analysis on electrical stuff sure seems to collect flys. Balalozor is the biggest one and I'm sure he will show up here as well. I will ignore him
I was just looking for some pics for Cliff and found this pic that I would like to post in no uncertain terms as a warning.
This is a picture of the battery area of my newly acquired 1981 GS750EX. I bought it 1/20/2007 and this picture according to my camera was taken on 1/24/2007 4 days later. At the time the battery was weak and 1/2 full of electrolyte. The PO had recommended I change the battery so as I was doing this I was checking out the charging system.
So you know what you are looking at there are two OEM ring lugs for chassis (frame) ground that have been heated to the point that 95% of the insulation had burnt off or had curled away from the wire. This condition existed for the entire current path from one ring lug, to the point at which this wire connects to the black/white ground wires in the harness and then back to the other ring lug.
This wire was carrying a whole lot of current 30+ amps to fry the insulation off of a wire such as it did. Remember the charging system is only supposed to carry about 12 amp total and there is only a 15 amp fuse in the fuse box for the whole system. The only part of the harness that was charred were those parts that had direct exposure to the connector crimp in the harness which tied the two ring lug wires to the rest of the grounds in the harness. In other words the current was not coming from the harness. If it had of been it would have blown the 15 amp fuse which would not have allowed the current to flow in the first place. So clearly we are looking at a situation where very high ground current (>>+15 amps) is flowing between the two ring lugs.
The only other evidence of heat damage I could find were in the three stator wire connections to the R/R. These had obviously been hot, as the wire was stiff and the insulation distorted. I can't remember now for sure if there were OEM or had been changed, but my guess is it was all stock.
For reference these two ring lugs are mounted to :
1.) The front mounting bolt of the battery box (under the rubber washer spacer) to establish a frame ground.
2.) The solenoid on the side mounting plate to tie that rubber mounted plate to the frame ground.
As far as I can tell the changing system, stator, R/R and the harness was all OEM and stock including the single stator wire that ran to the headlamp switch.
I'm pretty sure I remember other members here describing a similar condition.
So here is what I did.
1.) Replaced the connections between the stator and the R/R removing the leg going to the headlamp switch.
2.) I replaced the wires and ground lugs attached to the harness.
3.) Made a heat sink from copper tubing to be mounted under the R/R.
4.) I acid dipped and flowed solder into all of the fuse box crimps.
5.) Added a ring lug to the R/R ground frame mounting that connection.
6.) Made a ground wire to strap directly from the R/R frame mounted ground to the Battery (-)
7.) Made a ground wire to strap directly from the solenoid to the R/R frame mounted ground.
8.) I DID NOT CHANGE THE R/R and I DID NOT CHANGE THE STATOR.
Guess what complete charging function was restored with no more than 0.25V between R/R (+) and Battery (+) as well las between R/R(-) and Battery(-) as measured at 4000 RPM. The Battery voltage at 4000 RPM when to about 14.5 volts.
I verified this with a second OEM R/R from a parts bike with virtually identical results. Finally rather than temp fate, I swapped out the stator for an Electrosport model as the insulation is old and prone to shorting. There seemed to be a drop in the A/C output voltage under no load testing, but there was no significant change to the overall system charging function as I recall.
Here is the heat sink that is under the R/R. I used the EMI gasket material with heat sink grease to create a good thermal ground to the frame by bolting the curved sections to the frame section directly above the R/R.
EDIT: I was a little inconsistent and changed the ground some; Here is a final configuration:
By picking one of the R/R mounting bolts as the single point ground point, the R/R(-) wire can be very short, the mounting plate is automatically grounded and all of the return current wires can be tied securely together at a single point. Here are the connections
- #1: Ground R/R(-) to case and side plate
- #2: The shortest wire to a frame bolt
- #3: The shortest wire to the Battery (-)
- #4: Connects to the (B/W) harness negative ring lugs (typically the one attached at the solenoid mounting bolt). You can leave the other harness ground ring lug (B/W) where it normally is picking up the battery box ground.
Here is a matching picture on a GS750EX, it will work well for most all E's at least. The layout may be a little different on the G's and L's but the ideas will be the same.
So what is the moral of this story?
There is a FUNDAMENTAL and LATENT design defect in the overall GS charging system, that allows perfectly functioning components to smoke the harness even with a properly functioning fuse box. I call it a design defect because overall the system was subjected to connection degradation alone and it caused the destructive behavior without having any defective (i.e. broken) parts.
My assessment of what happened in that:
a.) high current flowed from ring lug to ring lug.
b.) The current did not pass through the battery as the battery is fused at the + terminal
c.) The ground current is related to a stator current flows.
My assessment of how it happened is incomplete:
a.) We know that there is nothing preventing or limiting current flows in the stator or inside of the R/R.
b.) There are only two possibilities for the direction of the ground flow which are:
i.) the R/R ground sourced current.
This would be very unusual unless the one of the stator connections were so bad that there was an alternate lower signal path to complete the 3 phase stator current paths.
ii.) The R/R ground sunk current.
This is the normal operation, but that current flow is not from the GS load.
The above analysis supposes that the schematics provided in the Suzuki manual are connect, however since we really don't know what is inside of the OEM R/R's there could be something else going on.
The discovery of these burnt wires has spurred me to try and determine a mechanism for the current flow. The best I can figure is to make sure that your grounds are good and possibly get away from the OEM R/R. I'm moving to FET based versions as then are both newer and more efficient. With the FET design the FET control is separated from the power device, and so this is fundamentally different to the other shunt regulator devices from a circuit topology standpoint. This is maybe additional benefit of the FET devices.
Pos
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