Topic: 400F wiring harness

[Killer Canary]

Hello folks,
some character in my bike's past saw fit to chop the wiring harness off just forward of the coils.
Using a complete example, I've completed mine using the same colour codes.
There is a mass of connecters under the front of the tank; in the manual it looks like both handlebar switches connect here.
Does the main ignition switch wiring also connect under the tank?
Is it just the instrument lights, forward signals and idiot lights  that connect in the bucket and/or a combination of bucket/under tank connections?
Any help will be greatly appreciated.

[Bodi]

There is a mass of connecters under the front of the tank; in the manual it looks like both handlebar switches connect here. True!
Does the main ignition switch wiring also connect under the tank? No! The wires continue to the switch plug, no other connections
Is it just the instrument lights, forward signals and idiot lights  that connect in the bucket and/or a combination of bucket/under tank connections? Yes. Plus the headlight, horn, and brake light pressure switch - some of them may go direct with no bullets. I can check but it's kinda cold to go look right now...

[Killer Canary]

Thanks Bodi, no need to go check; after closely scrutinising the diagram, I realised that unlike the 550, the main lights (dash, headlight, taillight) won't light without the engine running as they feed directly off of the reg.
Thank you for your help once again.
Hope I can pay it back sometime.

[Bodi]

What you say is confusing. The regulator output goes only to the battery. The 400-4 lights are powered through the main fuse, key switch, then the two lighting fuses. The tail light also gets powered directly from the main fuse in "park" but that's a side note. Instrument lighting and brake light work whenever the key is on. Without looking at a diagram I don't know where the signals power from. This is on a model with no lighting OFF switch, but it just affects head and tail light.

[Flyin900]

The headlight and signals and taillight don't run through the regulator. I just wired a CB400F and with the ignition on the power is there to light all the aforementioned items without the engine running.
Trying to rebuild that harness is a big job and a replacement harness is available for $80 new from 4 into 1 or David Silver Spares with all new connectors and wires ready to go.

[Bodi]

What you describe - lights from the alternator only - was common on 2-strokes with magneto ignition, a generator/alternator powered the lights so you had no lights unless the engine was running. The Honda 400-4 does not work that way. The entire bike runs off the battery, and the alternator is connected to charge the battery and, of course, it powers the bike as well when running while any excess power charges the battery. Once the battery is fully charged the regulator controls alternator output so it just makes enough power to run the bike without overcharging the battery. In actual riding, the battery is discharging if below around 3000RPM as alternator max output at low RPM is less than the combined ignition, regulator, and lighting load.

[Killer Canary]

I was scanning the schematic between paint coats and couldn't concentrate much.
I've got everything but the main lights working.
Must troubleshoot that circuit.

[Bodi]

The 400F has a dirty trick in the lighting circuit. The harness is set up for a lights on/off switch but a lot were made with always-on lighting, the right switchpod was modified to delete the on/off switch. But the harness wiring still expects that switch. So they added a jumper in the right pod sub harness, just tucked into the sleeve. It joins a brown/black wire to a black wire... when the ends are plugged into the ratsnest under the tank you get lighting power. The jumper easily falls out and gets lost when working on wiring and is not included in replacement switchpods. Try jumpering the brown/brlack in that connector swarm (the harness ends, not the switchpod ends) to a black wire, you will probably have lights on.
If you have the shop manual wiring diagram, this jumper is shown just to the right of the "Speedometer Illuminating Light" text.

[Killer Canary]

!!!
Thanks!