big voltage output

[prestonblast]

Hi everyone, numpty question coming up- is it really possible to get over 100 volts out of my J50. Ive measured the voltage at the headset and this is the reading I'm getting. Ive lost all my lights except brake light.

Thank You

[fraggleexport]

Pretty sure thats possible chap!

I take it your regulator has blown? which in turn means your bulbs have blown

[prestonblast]

Thanks for reply.
Its an old 6 volt system so when you say regulator is that the coil?

[fraggleexport]

No, afraid not.
I'll throw you the basics but you may know some of this.
Your stator plate is fixed. You have a flywheel spinning around this. This movement induces a voltage from the coils on your stator plate. Different stator different amount of coils, but generally you have one or two for the lighting and braking bulbs and one for the ignition.
The lighting coils produce this voltage and the faster you rev the higher the voltage is. Up to 100v or more
Your bulbs need 6v only to shine bright. Any more and they will shine even brighter, but get to a point where they'll just blow. I'd suggest this to be around 12-20v.
So for that reason you need something to 'cap' your voltage to 6v (or 12v in a 12v system). This is your regulator. You'll have many volts going in and 6v going out. This 6v will then be distributed to your lights and brake system. If you want to try and measure this (which I guess you've already done) you need to measure AC Volts or VAC or the squiggly wave on your multimeter.
Your main coil (or HT coil as its also known) is involved with the ignition system. This accepts a voltage from your points and bumps it up to a massive voltage that then trots off to your spark plug. This does this 1000s of times a minute...
So....to conclude!....try and find your regulator voltage in and out. Id guess that its not working and youre seeing the same voltage out as you are in.

[wack 63]

No regulator on a J50 unless it's had a 12 v conversion. I really can't see a 6v stator kicking out 100v , the green maybe. Test each individual lighting wire at the frame junction box and also all earths,

[fraggleexport]

Whoops! OK Wack my mistake Ive just only had bikes with regulators....

Just for my interest now, how do the bikes regulate the coil voltage then?

[prestonblast]

Apologies to all.
It isn't a old fashioned coil as I've found the blue Ducati cdi Are these always 12 volt or can they come in a 6 volt version? I can't see any markings on it.
I also can't see a regulator, it seems to go from the stator to the CID and then straight to the loom, is this possible?
Thanks again for all replies.

[fraggleexport]

Almost certain they are only 12v Ducati cdi's. Try not to keep thinking coil when you mean Cdi (if you mean cdi!!) If you have a Ducati CDI you'll still need a coil. Trace the spark plug lead back from the spark plug. The thing it goes into first is the HT coil. From there it heads to your blue ducati cdi.

Regulators are sometimes fixed around the other side of the bike(left hand side) in the spare wheel well. Not sure about 50's though. Type in Vespa regulator to Google images. Its the silver thingy youre looking for.

Just out of interest Preston was this a happy working scoot before you posted this problem?

[prestonblast]

The scooter has been fine for 18 months until now.
I've traced the wiring and I can not see a silver regulator. From the stator wires go to a junction box then to the blue Ducati cdi then to the loom.