Jim's 1980 SG Miss September

I'm looking forward to seeing how Captain OCD does his wiring! Haha! I'm guessing it'll be tidy! :laugh2:
 
The Haynes manuals use the bullet symbols. On the G, SG, H and SH the output (red wire) from the rectifier splits with one lead going to the battery via the fuse and the other direct to the ignition switch. It looks like the fuse only covers the charging circuit at first glance. If you short the red wire going to the ignition switch then this will kill the bike and any power coming from the alternator. Power is still rapidly drained from the battery which then blows the fuse so that all is safe i.e. battery is now isolated and not burning up the harness. So the fuse does provide protection for both the red wire going to the ignition switch and the charge circuit. It also provides protection for the wires from the ignition switch to the fuse box.
 
So the fuse does provide protection for both the red wire going to the ignition switch and the charge circuit.
Paul, That's not how it's drawn on the diagram I just threw away. If you look at that one, it's a direct shot from the batt. to the ign. switch. No protection whatsoever. I just glanced a my Yamaha manual... It's not drawn that way.
 
Jim, I have the Haynes diagrams and if you want I will scan and post it. Just tell me which you want out of G/SG/H/SH.

OK.
 
Damned nice of you to offer Paul:) At your convenience... I wouldn't mind a look at the SG.
 
SG Wiring as PDF and Color Code as JPG:

ColorCode.jpg
 

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Yes, that diagram you were going to refer to is wrong. The wire to the key switch should run to the reg/rec and the wire to the reg/rec should run to the key switch.
 
Thanks Paul!! I just compared it to the Yamaha manual. Looks to be an exact copy and paste job... even down to calling the starter solenoid a "switch.";)
 
I suspect there is a mistake on the diagram I posted:
  1. On the SH diagram it is obvious that the Brown wire from the ignition switch splits to give Brown, Red/White and Red/Yellow and these plus the red wire gives the 4 separate inputs to the fuse box.
  2. On the SG diagram immediately below the fuse box I believe there is a black dot missing to show that the Brown wire also splits to give R/W and R/Y.
Assuming I am correct then in order to use your fuse box you must do as 5twins suggested earlier:
  1. Insert an inline 20A fuse for the Red wire so it does not go via your new fuse box.
  2. Connect Brown (from ignition key) to the Screw/Nut on your fuse box and then choose 3 of the 4 fused outputs to be Br, R/W and R/Y.
This leaves one spare fuse for an auxilary of your choosing e.g. electric fan for when it is hot.

Enjoy the Challenge.
 
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The wiring diagram for the USA G model does show the black dot but it is missing from the SE and SF.
 
Assuming I am correct then in order to use your fuse box you must do as 5twins suggested earlier:
  1. Insert an inline 20A fuse for the Red wire so it does not go via your new fuse box.
  2. Connect Brown (from ignition key) to the Screw/Nut on your fuse box and then choose 3 of the 4 fused outputs to be Br, R/W and R/Y.
This leaves one spare fuse for an auxilary of your choosing e.g. electric fan for when it is hot.

Enjoy the Challenge.
What I'm hoping to do is access the backside of the new fuse holder and isolate one fuse with a cutoff wheel on a dremel. That way I can run the red from the battery to that one (20A), and from there back out to the ign. switch. The brown from the ign. switch will go to the lug on the front of the fuse block and feed the three 10A's. If I can't isolate one of the fuses..... then I'll go with the inline on the red... and have a spare.

And I agree... the black connection dot is missing on the brown wire.
 
That's why it helps to have several wiring diagrams to refer to. Many of them contain little errors. This site has about all of them, plus pretty much every service and parts manual. I advise you "get while the getting is good ....." as the site could fold up at any time. The downloads are all free .....

https://thexscafedotcom.wordpress.com/author/xscafe/
 
I suspect there is a mistake on the diagram I posted:
  1. On the SH diagram it is obvious that the Brown wire from the ignition switch splits to give Brown, Red/White and Red/Yellow and these plus the red wire gives the 4 separate inputs to the fuse box.
  2. On the SG diagram immediately below the fuse box I believe there is a black dot missing to show that the Brown wire also splits to give R/W and R/Y.
Paul,
the Yamaha G diagram shows the dot, and like yours the SG doesn't. I took my meter and verified that the brown, red/white and red/yellow are indeed connected to each other. I penciled a dot onto my SG print.... problem solved.
I guess my comment that they copied the Yamaha print was on the mark. They even copied the "missing dot."
 
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Since my fuse holder is shot, like most others this old.....

View attachment 111208

and wanting to go with the newer blade type fuses anyway, I ordered this one from Amazon...

View attachment 111209


It was 13 bucks and has good reviews. No brand name... so it's obviously Chinese. I like the idea that a red LED will go out when the fuse blows. A nice modern touch. It's 4.3" long, 3.9" wide and 1.6" tall. So.... I'm not sure there's clearance under the seat. Anybody out there know off the top of their head how much room there is?
If there's not enough room, I'll probly' put it under the right side cover.

G'da Jim,

Where did you buy that Fuse box??

GW
 
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