Grounding/wiring GS425

[Guest]

I'm trying to get my little bike back together and my memory is a bit foggy. I've completely lost the ground wire (from battery to frame) and don't remember the exact spot it went to. Anyone know where it goes?

I had enough sense to remember that the small gauge black/white wire is grounded under the solenoid. I'm running that SH-775 instead of stock R/R .... the positive on that connects into the harness and the negative is hooked directly to the battery. Other than the main ground I think I'm pretty good, but open to suggestions. Just PMed a forum member with the same bike for pictures but was hoping to get this together sooner.

Thanks in advance!
GSP

Mmm... Just found a second black/white coming out of the harness. I've tried the schematics but am lousy at deciphering them.

[Brendan W]

Generally the big earth wire goes to a stud on top of the upper crankcase or many machines have them connected to a bolt on the rear mount plate.
There should be two b/w wire emerging from the harness at more or less the same place. Originally one may have been on the starter solenoid plate and another at something like the airbox mounts.
Now would be a good time to consider a single point earth. Collect both b/w wires and the regulator earth and join them together close to the battery -ve post. I have them collected on the solenoid baseplate. The single earth point is then connected to the battery with a single, short thick wire.

[gspower]

I have a battery with more than one negative connector and could plausibly hook everything directly to the negative of my battery, then ground the battery to the engine. Is this advisable? Can anyone else chime in? I am sometimes mechanically brilliant but when it comes to electric it would seem I have the common sense of a four year old.

[posplayr]

Close to what Brendan said. Collect grounds and mount near the r/r(-) with one running to the battery ground. Don't hook them all directly to the battery.

also clean the fusebox and other connections between r/r and battery.

do quick test to confirm basic operation. Report the numbers.

[gspower]

Close to what Brendan said. Collect grounds and mount near the r/r(-) with one running to the battery ground. Don't hook them all directly to the battery.

also clean the fusebox and other connections between r/r and battery.

do quick test to confirm basic operation. Report the numbers.

I've currently got my SH-775 zip-tied (firmly, I might add, until I find a more permanent solution) to the frame, above the engine and below the gas tank. The R/R doesn't have to be touching metal to metal with the frame, as this is what the ground is for ... yes? Therefore, wouldn't the physical location of the R/R be irrelevant? Please correct me as I am the first to admit just how dense I am on this subject. There is no fuse box on the 400-450's -- only a single glass fuse, inline, within a plastic enclosure attached to harness (+). It is clean.

Thank you posplayr, Brendan.

[Brendan W]

Personally I wouldn't put it anywhere other than where it had plenty of fast moving cool air. The casing is a heat sink and putting it over the stove won't help it. I would always screw it to the frame or battery box.
Would do no harm to start cleaning all connections and plugs regardless of their appearance. Individually they may not amount to much but cumulatively they rob the lights and coils of a few hundred millivolts which can make a big difference to easy starting and sharp running.

[gspower]

Personally I wouldn't put it anywhere other than where it had plenty of fast moving cool air. The casing is a heat sink and putting it over the stove won't help it. I would always screw it to the frame or battery box.
Would do no harm to start cleaning all connections and plugs regardless of their appearance. Individually they may not amount to much but cumulatively they rob the lights and coils of a few hundred millivolts which can make a big difference to easy starting and sharp running.

While your concerns are no doubt valid, those familiar with the 425 know all too well that there is not a lot of room for large upgrades. I didn't know this when I bought the SH-775. It hadn't been generating a ton of heat for the month or so I ran it like that, though.

I'm more concerned about the location of the grounds at this moment - just getting it into a logical running configuration - before I delve into anything else. posplayr recommended grounding them somewhere close to the R/R and then grounding that to the battery, but my original question: Does the location of the R/R, and more importantly the "single grounding point" matter if I've moved the R/R from the stock area?

GS425.jpg
(See HERE for a larger picture)

The wiring diagram shows the battery grounded directly to the frame but does not specify where. It also shows a "ground" (separate from frame ground) on the contact breaker, starter motor, starter relay, and rectifier. What is a "ground" verses a "frame ground"? From the diagram I am assuming that the two B/W grounds coming out of the harness correspond with the starter motor and starter relay, although it does not specify. Additionally, it does not specify the precise location of any of these grounds.

Just trying to do my homework ...
GSP

[Brendan W]

While your concerns are no doubt valid, those familiar with the 425 know all too well that there is not a lot of room for large upgrades. I didn't know this when I bought the SH-775. It hadn't been generating a ton of heat for the month or so I ran it like that, though.

I'm more concerned about the location of the grounds at this moment - just getting it into a logical running configuration - before I delve into anything else. posplayr recommended grounding them somewhere close to the R/R and then grounding that to the battery, but my original question: Does the location of the R/R, and more importantly the "single grounding point" matter if I've moved the R/R from the stock area?

One way of doing it is to collect all the harness grounds and the r/r -ve together at the mount screw or bolt in the mount screw hole for the r/r itself and then run a wire to the battery -ve post. Close to the battery is preferable because it will minimise the voltage drop. In my case that would have meant lengthening the frame b/w wires to go under the battery box which I didn't want to do. So as a compromise I put the single ground point on the solenoid plate. You could put the r/r under the headlight as many older brit bikes did. The trade off is cooling against voltage drops over that distance. Most GS bikes seem to end up with the r/r under or beside the battery box. The single point ground could be anywhere in theory. It just makes sense to keep the wires as short as possible.

[posplayr]

One way of doing it is to collect all the harness grounds and the r/r -ve together at the mount screw or bolt in the mount screw hole for the r/r itself and then run a wire to the battery -ve post. Close to the battery is preferable because it will minimise the voltage drop. In my case that would have meant lengthening the frame b/w wires to go under the battery box which I didn't want to do. So as a compromise I put the single ground point on the solenoid plate. You could put the r/r under the headlight as many older brit bikes did. The trade off is cooling against voltage drops over that distance. Most GS bikes seem to end up with the r/r under or beside the battery box. The single point ground could be anywhere in theory. It just makes sense to keep the wires as short as possible.

The voltage drops between the R/R and the battery are minimized when the SPG is located closest to the R/R. I have described this many times, current returns to the R/R(-) not to the battery.

[gspower]

The voltage drops between the R/R and the battery are minimized when the SPG is located closest to the R/R. I have described this many times, current returns to the R/R(-) not to the battery.

Posplayr, I highly respect your opinion and apologize if I am sounding intentionally dense. I want to assure you that I am actually that dense. Assuming my R/R is wired beneath my gas tank, and assuming the (-) from the R/R is connected, at present, directly to the battery, where exactly would you decide to put the SPG? If my R/R(-) is connected directly to the battery, current does not return to it, no?

Jesus ... I am like a toddler trying at algebra. I'll take pictures of my setup if it helps any.

[gspower]

After reading posplayr's electric guide I put the SPG under the starter solenoid. Because of the mounting of my R/R it was impractical to ground all of my stuff there.

A quick walkthrough:
1) I've soldered the R/R (+) directly into the harness, 8 gauge to the stock 14 or whatever. Maybe this is a problem?
2) I crimped and soldered a loop connector to the R/R 8 gauge (-) and tightened it to the right screw on the starter solenoid.
3) I crimped and soldered both ends of a spare 8 gauge wire I had and connected it between the battery (-) and the right side of the starter solenoid. (My kind-of-SPG)
4) The two black/white wires coming out of the harness are connected to the left side of the starter solenoid. I did this because they were not long enough to connect to the right side.
5) The yellow/green wire from the starter solenoid is connected to the yellow/green wire feeding into the harness. I have a red/white wire that is not connected to anything as well as another wire not connected to anything. I am pretty sure this is correct.

The battery is reading at around 12.5-12.6v right now. Resistance is low throughout all of my soldering. I used my multimeter and touched the casing (-) and solenoid (+) before hitting Start. No reading. 0v. When I turn the key, turn the switch, and press "Start", I am getting a loud CLICK from the solenoid. Checked all grounds, checked all connections, repeat. Same result, same sound.

I then took a screwdriver and bridged the (+) and (-) on the solenoid. Nothing. No spark, no engine turning, no click, zero. Perhaps I didn't do it right.

Getting depressed. Anyone?

[posplayr]

After reading posplayr's electric guide I put the SPG under the starter solenoid. Because of the mounting of my R/R it was impractical to ground all of my stuff there.

A quick walkthrough:
1) I've soldered the R/R (+) directly into the harness, 8 gauge to the stock 14 or whatever. Maybe this is a problem?
2) I crimped and soldered a loop connector to the R/R 8 gauge (-) and tightened it to the right screw on the starter solenoid.
3) I crimped and soldered both ends of a spare 8 gauge wire I had and connected it between the battery (-) and the right side of the starter solenoid. (My kind-of-SPG)
4) The two black/white wires coming out of the harness are connected to the left side of the starter solenoid. I did this because they were not long enough to connect to the right side.
5) The yellow/green wire from the starter solenoid is connected to the yellow/green wire feeding into the harness. I have a red/white wire that is not connected to anything as well as another wire not connected to anything. I am pretty sure this is correct.

The battery is reading at around 12.5-12.6v right now. Resistance is low throughout all of my soldering. I used my multimeter and touched the casing (-) and solenoid (+) before hitting Start. No reading. 0v. When I turn the key, turn the switch, and press "Start", I am getting a loud CLICK from the solenoid. Checked all grounds, checked all connections, repeat. Same result, same sound.

I then took a screwdriver and bridged the (+) and (-) on the solenoid. Nothing. No spark, no engine turning, no click, zero. Perhaps I didn't do it right.

Getting depressed. Anyone?

Reading about your grounding, it all sounds about right. The whole idea (at least mine) for a SPG on a GS, is to stack all of the ground wires (except the one that runs to the engine) into one stack and bolt them to one place. That place for the SPG is selected so that the run from the SPG to the R/R- is as short as practical (like less than 12").

You are running some grounds to the left side of the solenoid and some to the right side. I would extend those wire needed to get them all to the same place or just make sure all of those ring lugs are clean and have contact cleaner prepping them to avoid further oxidation.

Not sure why your bike is not cranking over. But the solenoid is supposed to click when activated. Assuming it is clicking, then I have to ask is the starter cable connected?

If all is connected and you bridged the solenoid with nothing then the solenoid is not working. But then why is it clicking?

BTW, you cannot check resistance with an Ohm meter. The resistance is too low, under 0.1 ohms

[Brendan W]

Have you put back the big earth cable from the crankcase to the batt -ve?

[gspower]

I believe the starter cable (big black cable from the solenoid to the top of the starter, yeah?) is connected correctly. I will recheck that connection in daylight.

Brendan W, what big black earth cable? And what does -ve mean? The only big black cable I can think of is the one bolted to the top of my starter, feeding onto the solenoid.

Can't thank you guys enough. If you are in the NY areas and need a set of hands, shoot me a PM. Happy to help.

[posplayr]

I believe the starter cable (big black cable from the solenoid to the top of the starter, yeah?) is connected correctly. I will recheck that connection in daylight.

Brendan W, what big black earth cable? And what does -ve mean? The only big black cable I can think of is the one bolted to the top of my starter, feeding onto the solenoid.

Can't thank you guys enough. If you are in the NY areas and need a set of hands, shoot me a PM. Happy to help.

ve- is Brit-speak for Battery(-)

There should be a thick black wire from ve- to the back of the engine cases.
There is also a thick wire from the battery ve+ (Batt +) to the solenoid and that the follows through with another thick wire to the top of the starter. The solenoid completes the circuit when activated.