Wire Harness Question. Help

[BooRadley]

Im in the middle of a rebuild of my first cafe racer. Its a 1974 550 four and i'm doing a whole new lighting system and basically all new wiring, My question is i see alot of these bikes they change the wire harness and all the connectors are either gone on the other side of the battery or they have moved them. I'm completely lost on what to do and where to even start do they make a kit for that with all the relays and such, do I get rid of them and just do straight forward wiring , Im lost someone please help.

 

[Sonreir]

First rule of designing anything is to have a clear understanding of what you want from the end result.

Which components on your bike are going to require electricity? Until you can answer that, you won't be able to do anything useful to the harness.

 

[BooRadley]

I plan on having Led brake lights and turn signals, HID headlight, acewell speedo/tack with a neutral light, oil light ,hazard light highbeam light, and turn signal lights on it. plus i need to make a list of whatever else requires power in the engine like the coils and what not. Also make sure i can add accessories if i decide to put anything else on it. I have never taken on a full wire harness before. Im just looking for any pointers that will guide me along the way really. thank you

 

[Sonreir]

Get it all down on paper and you should be good to go. For a simplified diagram you can run a single fuse and common hot. If you want it a bit more complex you can run multiple circuits in parallel each with their own fuse. It's common to run the coils on their own circuit, headlight (both high and low) on another, brake, turns, and tail on a third, etc, etc.

Designing the harness is as simple as drawing a line from one component to the next. Just make sure to include switches where you don't want the electricity on all the time (e.g. brake lights, kill switch for coils, etc) and ensure that your AC and DC portions remain separate.

To get started, I usually like to make use of a stock diagram and then start erasing lines for things I don't plan to use. I usually delete all the ground wires and use the frame as common ground. I run as simple as possible in the wiring department, so only a single 5A fuse (which I need to upgrade to 10A since I've not gone with a 55W H4 bulb) and all the stuff that needs power runs directly from a common hot line.

Here's the most recent diagram I drew for my own bike... I'm still in the process of implementing it.

 

[BooRadley]

Thank you very much this helped a ton. Ill keep an update with pictures on my bike coming soon