Rewiring CB400SF

I'm working through a rolling restoration on my 1992 CB400SF (also known as an NC31) – it runs, but the existing wiring harness is a bit of a pig – years of bodge jobs from previous owners leaves me with constant issues with headlight/taillights failing, but generally everything else seems to run fine.

I’m planning on some major changes – stripping it down to the absolute bare essentials, new headlights, handlebars, ditching the indicators, relocating the ignition key switch, and cleaner wiring/minimal speedometer/tachometers to go with it all.

With this all in mind, I’m thinking that instead of trying to adapt the existing wiring harness I might as well completely re-wire things from scratch, based on this article http://www.bikeexif.com/motorcycle-wiringand this diagram:



I.e. – running basic accessories of headlight, taillight, horn, charging system, speedometer & tachometer, along with the water pump and radiator fan hard wired to always run.

With this all in mind, does anyone with a better idea of electrics & these bikes have any comments/pointers for me to bear in mind?

Cheers

Yours will be a bit more difficult than the diagram because of your electronic ignition. '92 might also include some "helper" sensors from the carbs for emissions. Make sure you have a diagram for your bike before you get started. Later models bikes usually send power to the solenoid (high side signalling) rather than ground through the bars (low side signalling), so there's that to keep in mind.

A lot of the wiring runs are as simple as making sure something has power, but make sure you understand what you're doing. It's not quite as simple as following a recipe; you really need to know what each run is doing of you might cook something.

The speed restrictor in the speedo is wired to the electronic ignition and apparently you need the restrictor connected for it to run.

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Here's my one

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Thanks Julian.

I'll try to understand how the restrictor works and if I can include it into new meters..

Nice bike.

Here are some diagrams I've collected to be used when I do the same on my cb500, not sure if they will help but thought I would offer them up.