Topic: Electrical how-to required!

[JBCB500]

I'm in need of even more help on my project 1973 cb500.  I've finished installing a new wiring harness, and I've put in a new battery with a good charge but I get no response from any lights, horn, etc.

I'm a complete electrics idiot and the manual doesn't cover diagnosis and repair of the main board. Does anyone have a how to for testing components, modernizing if possible, etc.  I am attaching pics of what I'm looking at now.  It's obviously very dirty and corroded in places, which can't be helping.  But I don't see anything that looks like a fuse to me, and I note a loose wire with boot - where should this go?

Any pics, videos, and write ups would be hugely appreciated!

[Scott S]

 First pic, top left....the white tube with red wires is the fuse holder.

[BomberMann650]

Lucky you these are straight forward machines and that is not a "board" like some sort of computer part.
Some manuals have a full color coded wiring diagram, that is your friend.  Provided you can physically differentiate between red and green 
If you have successfully matched all the right colors together, have scant other issues like corroded switches, buttons, broken ignition key or cracked/ruined clips - you should be able to have your electrics sorted in a relaxing evening at the shop.
As for modernizing your electrics, yes - that is one thing you can do to your bike simply, and affordably with a couple pieces from Oregon Motorcycle Parts.  I have complete confidence in my bikes charging system since upgrading to OMP parts, and they were direct oem fits.

[b52bombardier1]

Print out the wiring diagram on tabloid 11 x 17 paper for easy readability.  Starting with reconnecting the battery through the ignition switch, reactivate individual circuits one by one following the wiring diagram color code.  Do things one at a time until you are satisfied with each items performance. 

  You can't eat an elephant all at once but it can be done one bite at a time.

Rick

[calj737]

As Scott said, locate and check the fuse. Also, very important, on your bike every solid black is a switched 12v wire. These are NOT grounds. Solid GREEN is your ground wires. It's a bi unusual and wife's what you may have learned about red and black...

[madmtnmotors]

Here's a quick and dirty write up I did:

http://forums.sohc4.net/index.php/topic,137351.msg1549191.html#msg1549191

There are a couple more electrical related links in my signature below.

[strynboen]

take all komponents off the plate..and klean and paint it nicely..then klean evry part..for korosion and rebuild it on the main board..kontaktors can be glass blast,,and sprayed vith kontakt cleaner....other need to be painted to look nice...often all stuff vorks fine after a klean up..and some vires have to pun new inn
i have thanged mine fuses(nev model) and the solonid start relæ..but mostly hold the rest parts stock

[bochnak]

Kind of off topic, but you may want to replace the RR wires. I used the kit from oregon:

http://www.oregonmotorcycleparts.com/SOHCfours.html

It's the harness repair kit.

[pjlogue]

The wires going into your fuse holder look frayed (I can't tell if it is the wire or a frayed sheath to the wire) and the holder looks like it is partially melted.  Use a voltmeter to check for continuity across the fuse and repair any frayed wires then clean all connections.

-P.

[Duanob]

The wires going into your fuse holder look frayed (I can't tell if it is the wire or a frayed sheath to the wire) and the holder looks like it is partially melted.  Use a voltmeter to check for continuity across the fuse and repair any frayed wires then clean all connections.

-P.

They look more than frayed, they look fried!

[JBCB500]

Yeah, some of those wires were pretty crappy!  I've cleaned it up now and cut out the old style tube fuse holder and soldered in a new blade fuse holder.  These things are 15 amp, right?

[BomberMann650]

15A main 7a lights on 550's at least

[strynboen]

use a 3 fues holder...so you have 2 spare fuses at hand.(.in the holder)..i have a 5 fuses holder in mine use 3 of them as aktive...