Topic: 400F Wiring oddity?

[gregk]

My latest bike ( 77 400F North American model ) has some electrical problems.  I bought it knowing this.  I have spent quite a bit of time fixing what was obviously wrong with the wiring harness.  The PO had tried to graft bar controls from some other honda without sucess.  I have since obtained correct controls and installed on bike.  The wiring harness connections under the tank on the left side has a solid  brown wire with a blue end.  This is connected to a spliced wire into the black portion of the harness.  It looks like it doesn't belong with the original wires.  Without this connection, the tail light and the instrument lights will not work. 
I have since bought a second hand wiring harness and that harness had the SAME connection, even the same color wire! 
Was this an afterthought by Honda or just a common fix for some wiring shortfall? 


Greg

[GroovieGhoulie]

Not sure.  It's been a while since I looked at my wiring harness or a diagram, but I am pretty sure there were some factory splices.  Is the splice encased in a plastic sheath that is heat sealed at both ends?  IIRC, that's how the factory did the ones on my bike (a '76 400F) and that would indicate a factory splice.  Otherwise, if it's a cheap solder job wrapped in electrical tape or a twist connector, I think you have a Nocturnal Aviation connection.

Here's a 400F Wiring Diagram in PDF format.  It should help.

http://sohc4.us/files/wiring350-400F.pdf

[gregk]

The splices is definitely not factory as it is wrapped with electrical tape.  It just seems odd that both the wiring harnesses have the same jumper, same color wire etc.  Without this wire, there is no power to the fuse for the taillight. 

Greg

[bryanj]

Honda do splice different colours into each other, usually inside the loom where it cant be seen, but not always. It is probably to do with the US requirement for the lights to always be on but not 100% sure

[GroovieGhoulie]

The "lights always on" is accoomplished in the right-hand switchgear.  The plugs on the wiring harness that the US and ROW switches plug into are the same, but instead of installing a switch on the control, they solidly connected the wires.  You can buy a UK-spec Right-hand control from DSS right now for 35 pounds and it will plug right into your American wiring harness and you get the ability to turn your headlight off.

I am seriously considering it.

[Bodi]

GG is right. The US/Canada right control wiring harness has a splice inside the sleeve, connecting the brown wire to the black wire. If you're not careful and pull on either wire in those control harnesses, the 2 wires pull right out of the sleeve. Then you have to improvise (or try to stuff them back in). Also, if some PO has installed a non-400F Honda control housing (500, 550, whatever) with the same switches etc., it's identical except that spliced wire isn't there. SO... to get the tail-light working you need that very fishy looking jumper.
I like the idea of the UK spec switchgear with a lights ON/OFF switch too!

[JHansen]

Sweet!

Might be possible to check one's timing without depp sixing the battry, love the idea.

[gregk]

Thanks for the help.  I just can't get over the fact that both wiring harnesses have the same jumper, even down to the wire color etc.  The harnesses came from provinces apart so its not like the same mechanic or owner did both aplices.  Have attached a piture of the splice.  I can't find any reference to the brown wire in any wiring diagrams except for that strange brown wire in the headlight bucket which seems to to go nowhere!  The wiring diagram indicates that there are two brown wires from the ignition switch which join some where in the harness. 

Greg

[gregk]

Oh yea, the picture

[bryanj]

I still think it is to turn the sidelight(s) on when you aint got the on off switch on the RH switch

[TwoTired]

Sweet!

Might be possible to check one's timing without depp sixing the battry, love the idea.

Or, pull the headlight fuse for the maintenence proceedure.

Cheers,