Electricaltrickery issues...

[cal]

according to the diagram there is no earth to the bars,
Try taking the lhs switch off again and giving it a clean out, might be a bit of s*it in there causing the problem or something sprung out of place during assembly,
does the horn and pass light work ok? if they work but make the indicators glow(probably only the headlight will make this happen, but you could also connect a healiamp bulb to the horn connections to make it draw enough current, and not deafen you / piss off the neigbours) it follows that there is a faulty earth on the switch block wiring.

Also try disconnecting the front brake light switch and give it a try out then you may have fitted a faulty brake light switch, which is leaking power back to earth.

Brake light option would be the first at this point as its the bit you have changed in a prev working setup....and its easy!

[ssray]

With this sort of thing I normally start replacing the earths or tapping into them and earthing them to the nearest bit of frame
The main one`s from the starter motor and the battery could probably do with replacing, I always use higher current wire when replacing these bits too
Ray

[Tarwetijger]

8<
Does anyone know if there is an earth in the switchgear to the bars, or can decifer the wiring diagram above?

No, there is no earth on or trough the bars. In fact, at the light switches there is no earth at all. Earth (negative) is always black on a Yamaha motorbike and the wiring becomes black only after the light bulbs.
So it goes like positive - switch(es) - bulbs - earth/negative.
That your side lights effects your mean light and the other way around, indicates they are using the earth route of each other. This can only be because of some bad connection: your side lights cant use their own route to negative so the current tries another route trough other light bulbs.
In my opinion the easiest way is to check all black wiring from your headlight and meterunit back to the battery.
Could be just one of the plugs under the tank that is corroded, or something like that.

[Dav]

Replace the flux capacitor

[Mincehead]

It won`t help Dave but it made me smile! Yes, get your tank off and look at all those connector blocks up about the headstock, under the guages etc.

[Stankflapper]

Replace the flux capacitor

We all know if he does that he will need to then get metric neutrons,, more costs!

[trixynut]

Enough of the silly talk, this is serious!

OK, I disconnected the new rear light and the new front brake light switch and everything is still not working right.

The battery terminal earth is good, and the other earths I could see (by the reg/rec and the coils) also all seem fine. Not checked the one from the temp sender or starter motor yet.

Just seems strange this started as soon as I split open the LSH switchgear. I'd done nothing else anywhere else or even moved the bike off its stand.

I've had the switchgear apart and checked for any loose wires, took out the light switch and checked the connections on the slider switch and all seems as it should be.

Looks like the MOT retest will need to be cancelled. Maybe I should try with another LHS switchgear.

I feckin' hate electrics.

[ekoja]

Just a thought, but I seem to remember once that a similar problem was resolved when it was found that a bulb was faulty.
Don't ask me why or what.

[cobbadiggabuddyblooo]

why not disconnect the switchgear,find the power on the loom and use a wire to run power down each one and see if you have an individual problem .Would not this isolate the problem???? If not it's in your switchgear...

[trixynut]

Update:
had more time yesterday to have another fiddle in the daylight as its my day off.
Checked all connections on reg/rec, indicators, fuses, etc and all earth connections I coud find, following wiring diagram.
Nothing changed, so unplugged one thing at once, indicators individually, horn, sidestand switch, clutch switch, brake switches etc to try to narrow it down, but nothing! Tried it with bike running too. So plugged everytrhing back in as it should be, and the problem was still there.
Then ...... It all started working properly!
WTF?!?
Have a suspicion its something to do with the rear indicators, so disconnected them to try to replicate the problem but couldnt.
Is there an earth from the rear indicators? But ... If i disconnect, i just get the same as a blown bulb i.e. Fast flashing....
Really is a mystery and may occur again, but for now i am putting it all back together and praying!!
Dave.

[Mincehead]

Were any wires trapped, rubbed through their insulation? Maybe there`s two wires making a connection they are not meant to somewhere?
The large multi terminal relay on the front face of the H frame casting can get corroded terminals, perhaps it`s been something bridging terminals down there?
Anyway, give all the conectors a spray with ACF50 and leave it to see it it rears it`s ugly head again.