Honda-SOHC
SOHC.co.uk Forums => CB350/400 => Topic started by: SeanFD on January 25, 2022, 08:51:13 PM
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I've been working on the wiring of my little Rusty and have just got into the headlight bucket.
The parts fiche shows an item called "washer headlight case" used as a nut to hold the headlight in place (No 466 on the diagram)
[attach=1]
This had an earth wire attached (for the indicators as on the CB750K, I'm assuming) but I cannot see the reason for this as the indicators must be earthed on the mounting bracket – at least mine are.
Can anyone confirm this, which means the wiring is un-necessary?
If so also confirm the thread on the mounting bolts; I think it is M10x1.25?
Sean
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Probably used because its a standard part used on most Hondas, not sure of thread
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I've been working on the wiring of my little Rusty and have just got into the headlight bucket.
The parts fiche shows an item called "washer headlight case" used as a nut to hold the headlight in place (No 466 on the diagram)
(Attachment Link)
This had an earth wire attached (for the indicators as on the CB750K, I'm assuming) but I cannot see the reason for this as the indicators must be earthed on the mounting bracket – at least mine are.
Can anyone confirm this, which means the wiring is un-necessary?
If so also confirm the thread on the mounting bolts; I think it is M10x1.25?
Sean
I thought the earth was for the headlamp unit not just the indicators.
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If my memory serves me correctly, all the green earth wires from all the other fittings in the shell finish up in a multi connector, and this could be the main earth lead return as the shell is plastic. If I'm wrong, sorry. Blame Anno Domini, a good meal, and alcohol. Regards, Mike.
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If my memory serves me correctly, all the green earth wires from all the other fittings in the shell finish up in a multi connector, and this could be the main earth lead return as the shell is plastic. If I'm wrong, sorry. Blame Anno Domini, a good meal, and alcohol. Regards, Mike.
I'm pretty sure you're right. The headlight and indicator bracket is rubber mounted so not a good earth, hence the earth wires.
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Aren't there various rubber mounts that would make the earth route at least patchy on the fork ear ? Hence the need to have a competent earth strap to indicators.
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I had that issue a few months back when I was redoing my wiring. The green wires on these nuts are there to improve the grounding of the mounting bracket.
With the plastic shell, the paint and the rubber mounts, it is not the most conductive area. Had me scratching my head for a while as whenever the headlight lens and metal ring touched the front mudguard the lights would improve by 50% if not more compared to when it was on the bucket.
Turns out it was just the ground that was shite in that area.
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Thanks for the thoughts guys. I had considered some of those. But ...
Looking at the wiring diagram I have:
[attach=1]
There are 8 earth connections all coming from the main loom as shown in the pic, so the headlight bucket, being plastic as noted, doesn't come into it.
Unlike on the 750, the things that screw into these "washers light case" are just reflectors; the indicators are mounted on arms from the headlight mounting bracket, or stay as Honda calls it. Now although this is rubber mounted, I am still getting an earth connection on the indicator mounting bolts, which is why I thought the earthing nuts were, perhaps, superfluous.
The indicators were not working properly last night, so I'm going to go with Alexrayz's suggestion that the bracket is not well earthed. Off out now to test the hypothesis; I'll let you know.
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It does connect to the side reflectors but it also connects with the headlight mounting bracket. I guess this is where you're supposed to get your connection to the metal body of the bike. Crud can get in there and make it less conductive.
Best thing to do is to use a multimeter in continuity mode, attach the black probe to the negative terminal of the battery and then use the over probe ti check for continuity. Where it doesn't beep is where you have bad grounding.
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I connected the two wires, and ..... everything worked! ;DExcept one front indicator. :(
I decided to check the bulb and (this took a little while as I got distracted). The bulb was OK. I switched the two front bulbs anyway, and ... nothing worked!! :-[
Well not quite nothing; when I indicated left, the right instrument panel light worked, and when I indicated right, the rear left indicator worked.
I spent ages checking everything, and then noticed that the voltage at one point was only 8,5V. The battery I was using is on old one with a bit of history, though it does seem to hold a charge when not stressed.
I'm not sure why a low voltage would cause the strange happenings, but I put it on charge and moved on to other things. I will ry again tomorrow.
Oh, I did find out that the wiring and feed to the coils is OK; with the kill switch on "Run" the coils got quite warm. Which may explain my flat battery!!
Ah well.
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I connected the two wires, and ..... everything worked! ;DExcept one front indicator. :(
I decided to check the bulb and (this took a little while as I got distracted). The bulb was OK. I switched the two front bulbs anyway, and ... nothing worked!! :-[
Well not quite nothing; when I indicated left, the right instrument panel light worked, and when I indicated right, the rear left indicator worked.
I spent ages checking everything, and then noticed that the voltage at one point was only 8,5V. The battery I was using is on old one with a bit of history, though it does seem to hold a charge when not stressed.
I'm not sure why a low voltage would cause the strange happenings, but I put it on charge and moved on to other things. I will ry again tomorrow.
Oh, I did find out that the wiring and feed to the coils is OK; with the kill switch on "Run" the coils got quite warm. Which may explain my flat battery!!
Ah well.
We’ll shit, your bike is cross eyed!
Just out of curiosity, what was the issue that led you to work on the wiring?
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Ever seen an older car when someone indicates AND the brake light comes on (rear view) then the whole light panel flashes dimly ?
Ordinarily that's a compromised earth on one of the lights, the activity then tries to scavenge an earth through commonality with the other lights under the load the circuit is running at, making it look like a complex unexplained problem but in reality just an earth drop out.
As Alex mentioned earlier, worth tracking each component's earth back to battery to identify the fault.
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We’ll shit, your bike is cross eyed!
Just out of curiosity, what was the issue that led you to work on the wiring?
The bike was a restoration project, or rather turned into one - at first I thought I could just get it going and ride it for a while for fun. Then when I looked more closely ....
[attach=1]
[attach=2]
[attach=3]
I've repaired what could be repaired, replaced what couldn't and cleaned everything up.
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Ever seen an older car when someone indicates AND the brake light comes on (rear view) then the whole light panel flashes dimly ?
Ordinarily that's a compromised earth on one of the lights, the activity then tries to scavenge an earth through commonality with the other lights under the load the circuit is running at, making it look like a complex unexplained problem but in reality just an earth drop out.
As Alex mentioned earlier, worth tracking each component's earth back to battery to identify the fault.
I've now done that and will go and try it all out gain tomorrow when teh batter has charged overnight - with the coils disconnected this time.
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Yes the threads are 10mm X 1.25mm
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Looking at the rectifier connector pic it seems things got heated. There is a possibility that there is a short. When investigating electrical, I recommend printing multiple copies of the wiring diagram of your bike (careful as there are different versions) and mark with a fluo pen the different systems on different copies: like 1 copy is the blinkers, another the coils, etc. Helps making a mental map.
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