Topic: 1974 CB750 Electrical!!!

[Kcinnick]

I know I want to replace everything electrical in my bike.  I got it yesterday with plans to replace all electrical, but didn't realize HOW bad it was.

I know I need a new wiring Harness.

I am going to replace the positive and negative battery cables and fuse box. (would like to keep original)

I don't have my manual yet, but I want to replace EVERYTHING behind the left side panel.

Any help on what all I need to order to replace, right now it is just a rats nest in there, I can't make heads of tails, but lots of butt connectors and incorrect wire colors...

Also considering Replacing the starting components, Stator and Rectifier while I am at it.

My other two projects while doing this is getting a replacement left side bottom factory exhaust and new factory handlebars.  I am also rebuilding the forks, probably with an upgraded kit, just haven't decided which one.

Thanks for any info, hopefully I can answer some of my own questions with a manual, but I would LOVE to get parts ordered before the manual arrives, thanks to the holiday it will probably be the end of the week before I get it.  At least I got a running CB750 in pretty darn good shape because the kid didn't know enough to keep it running.  He kept chopping wires... 

Ultimately I hope to have a clean original bike, not necessarily 100% restored, but a nice bike in good shape that is close to original as possible.  They don't make bikes like this anymore and you won't catch me on a new bike.

[grumpy]

if you're completely starting over then I'd say get a new OEM harness.
then get some wire & connectors from http://www.vintageconnections.com/

honda actually did a really good job of color coding the wires so I'd stick with the OEM color convention. it makes a lot of sense if you study it.

[PeWe]

I thought that I had to replace all electrical stuff on the left side when when my CB750-76 had been sitting in a barn for 20 years. But NO, everything worked.... Only battery had to be replaced and new paint on battery holder.

I replaced the main harness 1983-84 so I knew it was fresh I had to order new pilot lamp harness from Japan, yamiya750.com
I replaced both handle bar switches that both looked bad.  All these stuff including fuse box can be found at http://www.vintagecb750.com and other sites as well.
http://www.vintagecb750.com/products/5/electrical/55/wiring-harnesses-and-charging-system-parts

This might be closer
http://www.cb750supply.com/products/5/electrical/55/wiring-harnesses-batteries-and-charging-system-parts

Why wait for the manual???
Download and read now!! http://www.honda4fun.com/materiale-documentazione-tecnica/shop-manual
Scroll down and you'll find CB750 shop manual in 6 files (eng).
The circuit diagrams can be found there. I attach K4 circuit diagram if that is the model you have

Edit: Check your main harness. I found it can be damaged when pulling, mounting the engine. Or, if a maniac electrician has damaged the wires where connected inside the head light.

[calj737]

All of that above is great info. To add to it:

You can buy from Hondaman (member here) his book (priceless) and he sells a plug and play Blade style fuse panel. No more glass tube fuses. Well worth the small deviation from stock for a stock + upgrade.

You can have the Stator rebuilt if it is bad, Rick's Motorsports in New Hampshire I believe. Oregon Motorcycles in the PacWest is another option. If you're determined to replace the regulator, you can choose a slightly different type of a combo solid state Reg/Rec unit, also sold at these vendors listed above.

As for your harness and headlight bucket: if you're keeping a stock location, stock orientation, then buy a stock harness. The mess behind the headlight won't get any less messy, (no where else to put it) but you can make or buy your "connectors" kits for sub assemblies and then at least you'll know they're in top condition.

If you're willing to deviate slightly from stock on your electrics, then you can dump the fuse panel, the rats nest behind the headlight, and spend about $400 on a MotoGadget M-Unit and M-button and have a super clean, digital controller for your bike. Still keeping the side panel location and stock color scheme for your wiring.

Picture of the M-Button in headlight (this is the entire wiring behind the headlight now)



Picture of the M-Unit that has all the switching, fuses and digital controls of the electrical system



I made my own harness since everything was simplified and substantially reduced. Color-coded electrical for idiots with labels at the M-Unit and M-Button for connections. Simple. Reliable. And modern.

[PeWe]

+Hondaman's book. I fully agree.
I have in the ordering/shipping process. An investment with short payback time.

[Kcinnick]

A picture of what it is suppose to look like behind the side cover wold be amazing.  Now their is a mix of butt connectors and black, green and wires going who knows where and even with electrical knowledge I can't make heads or tails of it.  They have modified butt connectors to go over the old bullet connectors and clips wires when something started causing trouble...  I know the wiring harness will fix 90% of the issues on the bike.  I want to stay as original as possible.  Looking at the bike, I could probably wire the thing without a harness, but I want to keep it original.  I need very few pieces to get the bike back to 100% stock.  Some parts that are cheap, I look at them as "might as well replace" since I am already in there.