Coil probs linked to on/off switch? :(

[Fireman Ash]

Just when I thought today I had cracked the Spanish puzzle and bolt her all back together I've had fun and games with the kill switch and was thinking it was may be coil related.

Is it still possible to get Motoplat NOS ones (If it is the coil)? It would seem that the on/off kill switch works when starting the scoot from cold and after a few mins when she's warm the switch for some reason won't kill the engine, strange. Could this be the breaking down of the coil as it heats up? I'm not sure how or why that may happen as I understood the coils job was to step up from stator LT to HT voltage for starting and AC from the stator to ignition switch and power to the on/off switch.

With the scoot running I don't seem to have any voltage up to the switch hence why it's not stopping the engine when the switch is operated e.g. no electrical current.

With the scoot running just to confuse things I by-passed the loom and run a new piece of wire cable direct from the existing coil connection (green as Sticky's 6v wiring diagram with battery) to the switch and it worked e.g. off when switch in off position when contact made and continue to run with the switch in the run position.

So it's either a broken wire which I can't explain as it had been working or the coil? I'm told that coils can only be tested with specialist equipment which I obviously can't do.

Any help would be appreciated and any ideas what it could be?

Cheers all

Ash, Torquay

[firekdp]

The green to the cut out switch is merely an extension of the stator feed to the coil, to cut the engine the switch shorts the power to earth (therefore no voltage at coil). So a broken green here would not affect the running only the ability to stop it.

[bristolmod]

sounds to me that the kill switch isn't earthing when pushed. On Italian LI's the kill button is earthed via the clamp which holds the KB in position. Presumably the Spanish set up is the same/ similar. Try removing the KB and making a good contact between the KB and the headset to see if that sorts it

Chris

[Fireman Ash]

Cheers both for your help.
On my Serveta the kill switch/indicator unit is positioned on the clutch side handlebar and is earthed to the lower headset internally. I have fitted a brand new switch unit but will check the earth today. I will also check for any obvious broken wires at the coil end and test the coil.

So what part if any does the battery via ignition switch play in relation to the LT part of the ignition circuit? does it on starting provide power from battery through the ignition switch to the coil to kick over and then once running stator power takes over?
Thanks again.
Ash

[bristolmod]

Battery should be purely for side/ parking lights; horn and stop light. It will have no effect on the ignition side of things

Chris

[firekdp]

Although your machine is totally DC, the ignition circuit is seperate and runs direct off the stator green. When either the switch or kill button is operated the power is short circuited to earth killing power to the coil.
In the off position in your switch the two greens are connected (ignition power earthed), and the red is disconnected from the red/brown to stop the battery discharging through the regulator/rectifier.
In the on position the greens are disconnected (allowing the engine to run) and the red is connected to the red/brown to allow battery charging and battery use.

[Fireman Ash]

Cheers all. Found by using a multimeter continuity test this morning a broken wire from the coil to the switch unit which I've replaced and all seems ok....for now!!

Thanks again

Ash