Electrical problem.

[VAL. H.]

Need some advice here guys.

Knowing the bike started and ran before this problem is the starting point.

The bike: 1989 R80RT Mono outfit.

It all went wrong when I started the bike after fitting leading link forks as detailed in my other thread.


There has been a power surge of some sort, which has taken out something, I'm not sure what??????

I pressed the starter and it fired up straight away.... But the starter motor didn't disengauge for a second or two (literaly 1 or 2 seconds). Then the neutral light went out and it stopped. Hmm?! switched off and on, lights came on pressed the button, it fired up, then lights out and stopped. Did this a few more times with no joy.

The next morning I turned on the ignition. The dash lights came on dimm, then brightened and I could hear a realy quiet fizzing noise coming from somewhere up front. Then the dash lights went out. I did not try to start the bike.

What could this be?

Battery is good with good charge.


So far, I have removed, stripped and cleaned the starter. It was quite gummed up in the bendix. Bench tested and refitted and tested again. All good.

Then I started checking the electrical connections and relays. In the process of checking connections, I inadvertently put the lighting relay in the starter relay's slot. That did it. Lots of smoke, a lovely red glow and a burnt out earth wire down to the neutral light switch. Oops.
I've now traced and replaced the wiring and fitted new starter and lighting relays.

Now when I turn on the ignition, I get, parking lights on first click, correct. Then on second click, I can turn on and opperate all the lights, brake lights and indicators. But no dash lights, no ignition, starter button does nothing.
I've pulled the starter and kill switches apart, checked, cleaned and reassembled and tested that they work at the relay.

Prime suspects:

I'm thinking one or more of these is the culpret, but have no idea how to test them.
Regulator,
Diode board,
Hall sensor,
Ignition amplifier.



Any ideas?

Val.

 

[ChasF]

If it’s not cranking (and it’s in neutral) then it must be the starter motor or the connection to it.

Might be the kill switch/starter button wiring at the socket just under the front of the tank on rhs - had trouble with that myself.

 

[VAL. H.]

If it’s not cranking (and it’s in neutral) then it must be the starter motor or the connection to it.

Might be the kill switch/starter button wiring at the socket just under the front of the tank on rhs - had trouble with that myself.

Thanks, I'll have another look today. But I have already established a contact from the switch to the relay, through these connectors. They have been pulled apart and cleaned, as have the switches.

I'm not getting any lights on the dash other than those for the lights, ie the blue hi beem etc. No neutral light, no oil light, no ignition light.



Val.

 

[ChasF]

Just read your original post more carefully. I doubt the problem lies with the regulator/diode board or the ignition parts but you could just disconnect these for the moment and it shouldn’t affect the starter motor circuit which is the first problem to be resolved. First questions: Have you checked the fuses? Does the starter relay click when you push the starter button? Are you still getting the fizzing noise?

 

[squibb34]

Electrical gremlins in an old airhead - I'm wondering what the electrics behind the dash, ign switch & wiring around the headstock are like, after 33 yrs.

Surely some of this will have been shifted around during the fork change. Just the odd damaged/broken earth/neg connection will create all manner of strange issues, but it's easy enough to run a few temporary earth wires direct from the battery as part of the test regime.

Then there is the diode board (was the battery disconnected during the fork chop?), but, as ChasF says, take it one step at a time, otherwise you end up chasing ghosts.

 

[VAL. H.]

Just read your original post more carefully. I doubt the problem lies with the regulator/diode board or the ignition parts but you could just disconnect these for the moment and it shouldn’t affect the starter motor circuit which is the first problem to be resolved. First questions: Have you checked the fuses? Does the starter relay click when you push the starter button? Are you still getting the fizzing noise?

Fuses checked, more than once. Both good. Pulled the diode board off again to see it if did anything odd with the ohm meter. Don't think it did. Everything seemed to make sense. Starter button gives a signal as does the kill switch. I get a connection from the relay to the starter trigger. If I use a jump lead direct from the battery to the starter trigger connection, the starter turns the bike over. But no ignition, no spark no start. Starter does not react to the button, but I didn't expect it to as there are no ignition lights.

I'm being continually drawn to the diode board. Will the starter/ignition will work without it?

Electrical gremlins in an old airhead - I'm wondering what the electrics behind the dash, ign switch & wiring around the headstock are like, after 33 yrs.

Surely some of this will have been shifted around during the fork change. Just the odd damaged/broken earth/neg connection will create all manner of strange issues, but it's easy enough to run a few temporary earth wires direct from the battery as part of the test regime.

Then there is the diode board (was the battery disconnected during the fork chop?), but, as ChasF says, take it one step at a time, otherwise you end up chasing ghosts.

Plenty of ghost chasing going on. Being dyslexic isn't helping either.

 

[Nin]

There could be anything and everything going on there.

If the loom is cooked you could be getting earth and live leaks all over the place, which will take ages to track down and you may never get them all.

I hate wiring (and I’m dyslexic!) so I peel your fain.

I’d be tempted to get or make up a new loom and start from scratch - might seem drastic, but it might take weeks chasing the faults down.

Alternatively, you could step through each sub circuit (ignition, charge, lights, etc) and with a known good earth, try jury rigging up a new temporary loom. That’s what I ended up doing for my Guzzi T3 build.

Good luck!

 

[Beemerboff]

In my experience Nin is correct, I was faced with similar problems and have never regretted replacing the the loom.
Well I say loom , but when I pulled it i there was no loom as such just a mess of hard old corroded brittle and burnt wires!

 

[ChasF]

Given that you’ve already had an ‘external’ meltdown (wire to the neutral switch) suggest that Nin may well be on the right track. You should be able to disconnect the entire charging system and it shouldn’t have any affect on the starter motor (or any other circuit).

3 possible courses of action: 1/ fit a new main loom if you are confident that the sub looms such as wiring to the handlebar switches are OK, 2/ Open up the existing loom and splice in new wires (very time consuming) or 3/ carry on as you are now but the problem will be if one circuit works in isolation things may become very confused when other circuits are connected due to internal shorts.

 

[timeandtide]

I’m of the same mind - that’s why mine’s with Mikeyboy as we speak, for a new loom as I’m not very good with electrics . . . . or anything else come to think of it!

 

[VAL. H.]

There could be anything and everything going on there.

If the loom is cooked you could be getting earth and live leaks all over the place, which will take ages to track down and you may never get them all.

I hate wiring (and I’m dyslexic!) so I peel your fain.

I’d be tempted to get or make up a new loom and start from scratch - might seem drastic, but it might take weeks chasing the faults down.

Alternatively, you could step through each sub circuit (ignition, charge, lights, etc) and with a known good earth, try jury rigging up a new temporary loom. That’s what I ended up doing for my Guzzi T3 build.

Good luck!

In my experience Nin is correct, I was faced with similar problems and have never regretted replacing the the loom.
Well I say loom , but when I pulled it i there was no loom as such just a mess of hard old corroded brittle and burnt wires!

Given that you’ve already had an ‘external’ meltdown (wire to the neutral switch) suggest that Nin may well be on the right track. You should be able to disconnect the entire charging system and it shouldn’t have any affect on the starter motor (or any other circuit).

3 possible courses of action: 1/ fit a new main loom if you are confident that the sub looms such as wiring to the handlebar switches are OK, 2/ Open up the existing loom and splice in new wires (very time consuming) or 3/ carry on as you are now but the problem will be if one circuit works in isolation things may become very confused when other circuits are connected due to internal shorts.

I’m of the same mind - that’s why mine’s with Mikeyboy as we speak, for a new loom as I’m not very good with electrics . . . . or anything else come to think of it!

Thanks gents,

Looks like I'll be reopening the loom today. New loom, £290 outch.

 

[Steptoe]

Thanks gents,

Looks like I'll be reopening the loom today. New loom, £290 outch.

Be thankful it's not a /7 or earlier loom

 

[mikeyboy]

Be thankful it's not a /7 or earlier loom

Indeed,
Late para GS,main loom and engine harnesses,over£500

 

[VAL. H.]

Be thankful it's not a /7 or earlier loom

Indeed,
Late para GS,main loom and engine harnesses,over£500

Well, Fingers crossed it's not the loom. Err, from my very marginal knowledge of how to use/read a multimeter.

I stripped the loom back to the headstock and I did find a couple of things that needed fixing. A thin red wire was broken off and when I started to explore closer, another came off. These where from the point where several red/live feeds come together. It turned out that the one that was broken just went to a plug for the handlebar switches, but did not continue further. One of those extra wires not used on this model. Fixed that little lot so all good there.
Next thing I found was a black wire that had been chafed and a little bit exposed. Cleaned and taped this, now good.

Put the whole lot back together.... No change.....????

I then took the back of the speedo off, to check the connections. This is fun, because of the sealed wiring you don't know what connection goes to what colour wire. After some time with the ohm meter I established a connection to all points.




However,
I did get a puzzling result when I turned on the ignition to the first click (parking lights) and the neutral light came on, I was able to press the starter button and the started turned the motor over. I pulled a plug to see if I had a spark (fuel tank is off so no petrol in carbs) This time when I pressed the button, just a click at the starter relay. Checked battery, 12.5 volts, put it on charge.

What I found was, that this occurred when the earth connection from the loom (not the main battery earth) connected to the frame at the ignition amplifier was not attached.

Is this a normal thing to happen if the earth contact is broken?


I'm still thinking one of the electrical attachments is causing this. Other than that I don't know were to go.



Val.

 

[VAL. H.]

OK, Here's a definite.

When the earth wire pictured above is disconnected from its point on the heatsink of the ignition amplifier. Turning the key to position one 'parking lights' I get the ignition light and neutral light on the dash. The engine turns over on the button. But there is no spark. I do not get parking lights.

When I reconnect this earth wire, there are no lights on the dash from any position on the key, only the parking lights, now working as expected, and on second position, all other lights/indicators as should be. Starter button does not function and starter does not turn.



Val.

 

[Nin]

Your starter motor brushes could be worn? Or the relay a bit cooked? Love an intermittent electrical fault, though I still have PTSD from my Guzzi wiring. I’m getting cold sweats and flashbacks just reading this!

Er, good luck is the only other advice I can offer.

 

[ChasF]

Something odd going on with the ignition switch is my guess. If your multimeter has a dc amps setting you could try measuring the current flow from the disconnected earth to the chassis/battery -ve for different positions of the ignition switch- not really sure what this will tell us but may confirm that the switch is knackered.

 

[VAL. H.]

Something odd going on with the ignition switch is my guess. If your multimeter has a dc amps setting you could try measuring the current flow from the disconnected earth to the chassis/battery -ve for different positions of the ignition switch- not really sure what this will tell us but may confirm that the switch is knackered.

I'll have a look at that tomorrow. It's quiet a multi talented meter, lots of settings, most of which I know not what. My farther bought it, didn't understand it and passed it on to me. No instruction booklet isn't helping any either.

With the loom earth disconnected the ignition and neutral lights come on in the park position. Engine turns on the starter button, no spark. Touch the earth to the frame, lights go out and parking light come on as should.

Removing the loom earth, obviously causes some sort of reversal in the system. Is this a normal thing to happen in electrical systems?


Val.

 

[ChasF]

I think there is a short to earth (or, more accurately, that brown wire) due to a fault in the ignition switch. When you reconnect the brown wire to the chassis it’s pulling the battery voltage down to the point that the lights go out but it’s not a direct short or the wire would have melted - you may be right that it’s a fault with the regulator or diode board.

 

[VAL. H.]

I think there is a short to earth (or, more accurately, that brown wire) due to a fault in the ignition switch. When you reconnect the brown wire to the chassis it’s pulling the battery voltage down to the point that the lights go out but it’s not a direct short or the wire would have melted - you may be right that it’s a fault with the regulator or diode board.

I have a Diode board on the way. I'll start there with fingers crossed it's not the regulator. Its screw are welded to the frame. The only way off will be with something damaging.


Val.