Dead Bike Recovered by AA

[mr.john.coates]

UPDATE: Here's the position, what does anyone make of this?

Problem: No electrics, nothing works. Bike going one minute, dead the next. Battery shows 12.5 volts.

Work done:
Swapped reg/rec for known good one - No change.
Pulled ALL connectors (as far as I can see, and I've had the fairing off) - No corrosion or loose wires.

Found that if I turn the ignition on, there is a very faint glow from the red oil pressure warning and neutral lights and the battery voltage drops to 6v. The lamps gradually get a bit brighter, but never much.

NOW, if I press the kill switch, lights get full brightness and battery voltage goes to 12.5 volts again and even the odometer comes on!

I've circuit tested ignition and kill switch functions, clean contacts and found all is ok, with infinite resistance when open and about .2 ohm closed.

This must point to something - any ideas what?

Thanks

[darkember]

Have you checked the side stand kill switch?? & double check/disconnect & clean all earth bonds.

[vtrjames]

does the warning lights work ok with the cdi units unplugged?

do they light up normal with stop switch in both positions?

[mr.john.coates]

Have you checked the side stand kill switch?? & double check/disconnect & clean all earth bonds.

Yes, seems ok, but I'll double check tomorrow to be sure. It's on a paddock stand and I could see the light come on dimly when I lowered the side stand. Tomorrow I'll measure the resistance across the connector with it up and down.

does the warning lights work ok with the cdi units unplugged?...

Now I need to try this. It's too dark now and earlier I could not get the connectors off - They seem very tight and I wasn't sure which bits were the locking tabs. Tomorrow it's time for brute force.

...do they light up normal with stop switch in both positions?

Not at the moment - Normal running position --> lamps very faint, big volt drop across battery.
Kill position --> lamps bright, battery voltage ok again. This is starting to feck me off !

[vtrjames]

try unplugging them, if that fails, use the multimeter to resistance check the earths. they must all be good, as i said i had a fault with my vtr im building where the dash lights were on but no odometer. its sounds most likely a poor or broken earth. there will still be 12v coming out of the battery but it reading 6 as a potential difference cos of the stray voltage in the earth circuit.

[mr.john.coates]

Still no joy, think I need a proper motorcycle electrician.

I've unplugged CDI things, no different. A few time flicking the ignition on and off the lights came bright and I hit the starter button and the relay closed. The supply to the starter motor is disconnected, so it won't go far. This happened intermittently and rarely. I've pulled most fuses out to eliminate fan motor etc. I've proved the ignition switch and kill switch are ok. I've bypassed the ignition switch with a length of wire (bike security, what security?) and checked all earths etc.

The main symptoms are still:

When switched on (or hot wired) battery drops from 12.5 to about 6v, and gradually rises to about 9v. Sometimes it rises to 12ish, when you can (could) get the starter relay to kick in. Nothing else then works, I guess because battery is too low.

As always, ideas or offers for the bike welcome.

[lloydie]

Have you tried unplugging every thing and testing it by connecting one plug at a time .
Also worth removing the tail light bulbs .
Have you disconnected the starter motor as this could be draining the amps .

[VTRDark]

Coloured wiring diagram for you.
Sorry the quality is not all that good.

To unplug the ICM (small box on top) the little tab pull outwards with a screwdriver blade and the ECU will just pull straight off, but a little nudge with a screwdriver blade in the middle grooved tabs helps. It's also a lot easier to disconnect if you slide the unit the other side of the bar that runs across the frame.

Check the engine earth, this does sound like either an earth problem or there is a short somewhere. I would also check the connection under the fusebox also. Push the little tab that holds the fusebox to the plastic and lift it up to investigate.

(:-})

[mr.john.coates]

Have you tried unplugging every thing and testing it by connecting one plug at a time .
Also worth removing the tail light bulbs .
Have you disconnected the starter motor as this could be draining the amps .

- Yes, every connector I can see is now apart, all I've got is a pile of fecking bits! Unplugging them made no difference - CDI things are also unplugged and on the bench looking sweet. The only things on are the clocks, because I need to see the lamps - I've unplugged them too, but no good.

- Tail lights on bench too.

- Starter motor +ve disconnected at relay.

Coloured wiring diagram for you.

Thanks

To unplug the ICM (small box on top) the little tab pull outwards with a screwdriver blade and the ECU will just pull straight off, but a little nudge with a screwdriver blade in the middle grooved tabs helps. It's also a lot easier to disconnect if you slide the unit the other side of the bar that runs across the frame.

Check the engine earth, this does sound like either an earth problem or there is a short somewhere. I would also check the connection under the fusebox also. Push the little tab that holds the fusebox to the plastic and lift it up to investigate

All done

If anyone could put a voltmeter across their battery with the ignition only on and tell me the volt drop that would be useful as a comparison. I think mines excessive and could be part of the problem. Mmm, what does it drop to if you press start?

[vtrjames]

thats weird, just tested as you asked battery voltage with ignition off is 12.74vdc, ignition on only drops to 12.45vdc

when i press the starter it drops to 10.6vdc

[VTRDark]

The starter will take us much juice as it can to turn the big twin over. But as long as it turns over then all is all good. Have you tried wiring the R/R earth directly to the battery.

(:-})

[mr.john.coates]

thats weird, just tested as you asked battery voltage with ignition off is 12.74vdc, ignition on only drops to 12.45vdc

when i press the starter it drops to 10.6vdc

Thanks, James.

"...voltage with ignition off is 12.74vdc, ignition on only drops to 12.45vdc..." this is what I would have expected. Something is draining current when the ignition comes on. Just once when I was fannying around with it, I flicked the ignition on and got bright lights, and volt drop about same as yours. I pressed starter button (motor disconnected) and it went to 2volts across battery and lamps died again. I'm chasing something very intermittent.

"... when i press the starter it drops to 10.6vdc ..." --- Is this with the starter motor turning the engine over or not?

Cheers, J

[Keith]

thats weird, just tested as you asked battery voltage with ignition off is 12.74vdc, ignition on only drops to 12.45vdc

when i press the starter it drops to 10.6vdc

Thanks, James.

"...voltage with ignition off is 12.74vdc, ignition on only drops to 12.45vdc..." this is what I would have expected. Something is draining current when the ignition comes on. Just once when I was fannying around with it, I flicked the ignition on and got bright lights, and volt drop about same as yours. I pressed starter button (motor disconnected) and it went to 2volts across battery and lamps died again. I'm chasing something very intermittent.

"... when i press the starter it drops to 10.6vdc ..." --- Is this with the starter motor turning the engine over or not?

Cheers, J

As the fault appears to be somewhere connected to the starter circuit I would be tempted to try swop out the starter switch gear on the handlebars just in case its old and shorting out somewhere. A short could be hiding in the bound wires coming from the switch too so would be hidden. The reason I come to this conclusion is because you said your initial problem happened just after starting and going along the road. If the switch gear is faulty it could have been giving you the drain as your rode away. Yes its a stab in the dark but when its intermittant then anything is worth a try. If you have someone close to you maybe they will come over and you could try it out by borrowing their switchgear to test?
Ok I will go get my coat now

[Pete.L]

Sounds like the battery is toast to me. If you are getting that much voltage drop and it's not pulling a fuse, I think the battery is finished.
Have you got another one you can try?

Pete

[mr.john.coates]

Sounds like the battery is toast to me. If you are getting that much voltage drop and it's not pulling a fuse, I think the battery is finished.
Have you got another one you can try?

Pete

Pete, I love you and I want you to have my babies

I took the battery off my Deauville (known to be good) and tried it and YES!!! A good strong pull on the starter relay and no more than 1 volt drop with the relay working.

I did not really consider the battery since the bike was always a good starter and the battery holds - and still has - a good terminal voltage. It must be fecked under load. My next worry (I'm a worrier, I've always a long list) is does the solution fit the symptoms? If the battery suddenly died would it cause the bike to stop dead, riding one minutes and coasting to the side of the road the next? I'm not quite convinced, but I'm happy to have found an answer. I suppose what I'm asking is, is the battery problem part of the failure, some other component failed and caused the battery to die, or is it the root of the matter?

All I need to do now is put the b8stard back together again!

Thanks, Pete, hopefully this is the end of this post, unless someone answers my worry!