Electrics

[Octavian]

Hi all, its driving me bonkers!

I was having various problems with the electrics on my 400 and the previous owner had bodged the lot and swapped wires around making it a nightmare to trace anything.  Anyhow, I have bought and installed a second hand wire loom with the correct colour wires that matches all the diagrams I have to hand.

Now it seems I have some dodgy connections, sometimes the headlight works, then it doesn

[PatM]

Hi Mate- electrics are at best fickle on these old bike- Youll need to go and look at someone eleses really to go through the wiring. I have the odd fault when I take my headlamp off- as thats wher most of the wires join and split.The bullet connectors are old and loose- thats how you get high resistance and wires falling out. What part of the world are you in? need someone local- Im in Maidstone.
Id stick with the original connectors- unless you know what you are doing and can solder CORRECTLY. Theres no reason, given the sysmptoms you have described- that your bike sholdnt work ok- its just the lighting circuit and those earth wires thats sodding you about.

PatM

[matthewmosse]

if really bad a dremel type wire brush can be used to clean original connectors in situ, often though it's just a case of very lightly sueezing the female connector in some pliers to slightly tighten it then reassemble the joint. Re the earths, I'd use a short length of wire with a loop connector (one with a 6mm hole) on one end thru one of the 6mm bolts on the bike in a convinient location, just clean the area with a wire brush and protect with petolium jelly.

[exvalvesetdabbler]

On the original 400/4 rear indicator stalks there was a male spade connector spot welded to the back of it.  They will most likely have rusted away or broken off.  Even if you find them ,with a decent coat of paint it is difficult to get a good earth on to the indicator base.  Same for the front indicator bracket.  I ran the green earth wires straight into the indicator bases and has been problem free. The Grommet might split with two wires  so bung up the gap with silicone.

Best Regards
Dave

[PatM]

Just to add something to all this- a bulb (car sidelight) and 2 wires soldered to it- with a crock-clip on one end is the best tool to find out which green wire does what- as said by the last post- the earth wires are weel shot and running a wire back to the fram may be the easiest fix.

[K2-K6]

If you don't have good earths then it'll run you ragged as the faults all look unrelated and tease you with what appears to be a mad logic. I usually meter the circuits off using a meter with a beep to confirm continuity back to the frame.

Bullet connectors, squeeze the female as already said and use small amount of vaseline to make them much more reliable and less suspect when it's damp.

[Octavian]

Hi all, many thanks for your responses, I guess its one of those trials and tribulations that we all go through with bike work!  You are probably right about the lighting/earthing being the route of all my probs.

As an update, I have wired the greens at the back to the frame now.  I am guessing that I need to pull out all the cables in the headlamp and start again as I am probably getting the greens muddled up in there somehow.

Also, after much head scratching, the rogue and lonely wire is actually brown & black with a yellow tag, its the 9th wire from my LH handlebar switch, and I suspect the switch might be from a different model (750?/US?) as there really is nowhere to connect it in the loom I have.

I like the idea of testing back to the frame, I have a multimeter and might give this a go when the mrs is watching x factor.

Cheers
all

[PatM]

Mines not an Import and I know there are a couple of wires in the headlight that do f all.

[exvalvesetdabbler]

Some wiring diagrams here.

http://www.oldmanhonda.com/MC/WiringDiagrams/MCwiring.php#class

It might be worth posting a picture of the switch assay, someone might recognize it, then you could look up the wiring diagram and work out the function of each wire.

[PatM]

I

[Bryanj]

The regulator dosn't  dump current on any of the Honda sohc 4's it alters the current flow to the centre coil

[Octavian]

Hey all, yayyy! Got all the indicators working, unfortunately though the LHS is blinking double speed so I will need to check the bulbs and connections on that side again.

I also got the headlamp working on position, headlamp, high beam, dipped, and main beam flash including all the corresponding lights in the displays.  For about 2 minutes, then they all went dead again after I switched the key off and on.... ho hum, needless to say my Sunday evening bike work finished quite promptly, almost with a spanner buried in the garage wall!

Regarding the switch, I think I am right about the extra wire.  I know there is a light blue/white and orange/white in the loom that for uk models is there for ....decoration.

[PatM]

Great!

well, at least you are on the home run! Indicator light winking wildly is one bulb not flashing as they are in parallel with each other, per side. In the mid seventies when my flasher unit packed up on my A100- i made one from a 12v relay and a bloody great 50mfd capacitor- worked a treat and all bits from work- marvelous!

I don't want to go out into the cold and risk my headlamp off- as Ive got a Cibe conversion and the wires only seem to go back one way- and any variation of this usually means no light or an earth wire off!
I'm sure you are right about the spares and their colour..

PatM

[Bryanj]

The light blue with white and the orange with white are from a US model and are for the front "running" lights in the indicators

[K2-K6]

Is it the ignition switch with 1st position for engine and an additional click for lights as well?

If so they where usually brass surface contacts on a rotating barrel inside the back of the switch and can get a) worn and b) crusty so worth a clean out to get reliable. contact cleaner may be effective but as far as I can remember the whole headlight current passes through this contact so it may be worth a dismantle to assess for reliability in the future.

I've done this on 750's and think the switch maybe the same one; if you remove it and get it to warm room temp then you can gently relieve the small wedges on the backside of the plastic barrel (be carfefull not to damage as they keep the assembly at the correct tolerance to give reliable contact in use) you can then gently clean all the contacts with very fine wet / dry 1000grit and some lubricant to get a almost polished surface. I reassemble with petroleum jelly although I think they were dry from new.