Author Topic: Feel silly for asking but... Negative ground wiring question  (Read 2788 times)

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Offline greenjeans

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Feel silly for asking but... Negative ground wiring question
« on: December 14, 2013, 03:48:02 PM »
For pretty much any Honda, negative ground from the battery can/should run directly to a good spot in the frame correct ?

I'm sorting througn some melted wiring for a buddy of mine on an SL350.   Wiring diagram appears to have the wiring from the battery go into
the main wire loom instead of just going to the frame.   Shouldn't the wires coming off the battery be a little more robust ?   Or would the thin stuff be fine since the bike does not have an electric starter,    Seems to me like it should go straight to the frame ???
« Last Edit: December 15, 2013, 06:47:26 AM by greenjeans »
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Offline rb550four

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Re: Feel silly for asking but...
« Reply #1 on: December 14, 2013, 04:23:56 PM »
Sounded strange to me so I looked it up  http://www.cmsnl.com/classic-honda-fansite/wiring_diagrams.php   here , all wiring seems to go back through the harness to the regulator , the rectifier, and a few lights. but this diagram shows a frame ground at the battery and one more at the top of the page which would explain the blinkers being grounded to the frame, otherwise it wouldn't make sense. right?
  http://www.cmsnl.com/classic-honda-fansite/honda_wiring_diagrams/SL350.jpg
or... I don't know your year
   http://www.cmsnl.com/classic-honda-fansite/honda_wiring_diagrams/SL350(K1-K2).jpg
    http://www.cmsnl.com/classic-honda-fansite/honda_wiring_diagrams/SL350(70).jpg
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Re: Feel silly for asking but...
« Reply #2 on: December 14, 2013, 05:21:00 PM »
" For pretty much any Honda, negative ground from the battery can/should run directly to a good spot in the frame correct ? "
 I like to go between the engine and frame using the engine mounting bolt.

" Shouldn't the wires coming off the battery be a little more robust ?"
More robust than what? No the thin stuff will not be fine as to the correct size I will defer to someone with more brain cells. Mine appears to be #8 maybe 6. I don't or would not go down to #10 even with out a starter someone will chime in with how to determine the correct size if not soon just keep bumping the post. I think maybe it would have to do with battery amps??


Offline greenjeans

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Re: Feel silly for asking but...
« Reply #3 on: December 15, 2013, 06:46:11 AM »
Here's the diagram I'm using.   Straight from Honda.


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Offline strynboen

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Re: Feel silly for asking but... Negative ground wiring question
« Reply #4 on: December 15, 2013, 08:49:16 AM »
 vith no starter ...5 ah battery..can only feed a few lights and horn. blinkers and so....so think the battery/ frame  viring are not to be used ..must be fine with green ground viring ca 2,5 kvadrat viring as on the diragram

the model with startmotor have a 12 ah battery..different story
« Last Edit: December 15, 2013, 08:53:10 AM by strynboen »
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Offline greenjeans

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Re: Feel silly for asking but... Negative ground wiring question
« Reply #5 on: December 15, 2013, 09:13:56 AM »
Thanks fellas - first bike I've ever had that didn't have an eletric start.   Just seems weird that nothing goes straight to the frame.

Wouldn't hurt to add one would it ?     This one has some aftermarket turn signals that ground to the frame.
« Last Edit: December 15, 2013, 09:15:45 AM by greenjeans »
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Offline Don R

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Re: Feel silly for asking but... Negative ground wiring question
« Reply #6 on: December 15, 2013, 10:15:13 AM »
I believe the dot in the wire to the lower left of the battery is a frame ground point. Sometimes a schematic only shows the electrical path and gives few clues to the physical location of an item.
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Offline Irukandji

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Re: Feel silly for asking but... Negative ground wiring question
« Reply #7 on: December 15, 2013, 10:53:41 AM »
Don... you are right

Upon higher magnify the "dot"  is a "G"
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Offline Bodi

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Re: Feel silly for asking but... Negative ground wiring question
« Reply #8 on: December 15, 2013, 11:12:04 AM »
The G is for Green. I don't see a specific ground point on battery "-", but several components work to ground (like the ignition points).  The ground will connect through the rectifier connector, but I would tend to add a good secure ground to the frame directly from the battery terminal.

Offline Irukandji

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Re: Feel silly for asking but... Negative ground wiring question
« Reply #9 on: December 15, 2013, 02:02:21 PM »
Don... you are right

Upon higher magnify the "dot"  is a "G"

My bad.  :-[  Goes to show to wait for several confirming posts before taking anything for gospel.
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Offline greenjeans

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Re: Feel silly for asking but... Negative ground wiring question
« Reply #10 on: December 15, 2013, 02:25:53 PM »
When I took things apart, there was no direct connection to the frame for ground.   But...in a case of WTF was the PO doing, I found that he had the postive end of the wire from the battery connected directly to a ground wire as well as others !! 

I've gone through the wiring and only had to replace about a foot or so of ground wiring.  Luckily, I had several old harnesses that I've collected over the years that I used for the green wires and a few extras that got hot.

I'm sure that the rectifier will be toast.   Somehow the voltage regulator wasn't even hooked up either.

We'll see...   I've added a ground wire to the frame as well.   Going to button everything back up and slap a new battery in there and see
what happens.
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Offline strynboen

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Re: Feel silly for asking but... Negative ground wiring question
« Reply #11 on: December 16, 2013, 09:28:57 AM »
put a ekstra green wire from.. negative battery to engine mounts, and then up, in to mainlight house..the one" forkear "have normaly a ground konneksion...but add a eksra vire from  battery/engine/frame..so the ground not have to move thrugh the stering bearing set.( if the  old vire are bad)..it gives a better light..and more power.. a 40 years old viring can need a back up
« Last Edit: December 16, 2013, 09:36:45 AM by strynboen »
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Offline lucky

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Re: Feel silly for asking but... Negative ground wiring question
« Reply #12 on: December 16, 2013, 10:28:57 AM »
Thanks fellas - first bike I've ever had that didn't have an eletric start.   Just seems weird that nothing goes straight to the frame.

Wouldn't hurt to add one would it ?     This one has some aftermarket turn signals that ground to the frame.

One ground from the battery to the frame.
One ground from the battery to the engine.
The ground for the starter has to be large because it is carrying a heavy load.

Offline strynboen

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Re: Feel silly for asking but... Negative ground wiring question
« Reply #13 on: December 17, 2013, 06:36:42 AM »
One ground from the battery to the frame.
One ground from the battery to the engine...


why not use the same  vire to both konneksions?
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Offline greenjeans

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Re: Feel silly for asking but... Negative ground wiring question
« Reply #14 on: December 17, 2013, 07:24:06 AM »
Looks like I'm going to have 1 going directly into the wiring harness, 1 to the frame and while I'm at it, I'll put another to the motor.

That should cover everything and give me a solid ground everywhere.   Thanks fellas.
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