Ducati 6 pole stator purple wire problems

[Gio695]

Hi,

My name is Gio, and i've been on the forum for a while, but i don't post much because of time (sorry for that)
I've worked on a number of Lambretta's (or engines) but never had this problem and it's driving me mad!

 

The Lambretta in question is an 1966 Italian 150 Silver Special. I've rebuild the engine but kept as much original parts as possible (also original paint etc).
The ignition is the original 6 pole Ducati, 6V, no battery!

 

I've been having a problem with the lights that work with the ignition switch in position 2, so the speedo bulb and bullet type lamp (position light?) and rear light.
The Lambretta starts without a problem, first kick every time with the key in position 1 or 3 (headlights etc)
but as soon as i put the key in position 2 it cuts out.
I've checked everything and even changed the complete wiring

loom, the ignition switch and the light switch, just in case... al ground cables and lamps are also new.
The problem seems to be the purple wire coming from the ignition!
If i put the brown cable in the place the purple needs to fit the speedo bulb and bullet lamp work!
If i put the purple cable in the position the brown has to be, the bike cuts of with the ignition switch in position 3!!

So, before you say change the stator....i already tried with a second one i had!!!

This is the weirdest problem i ever had.

Is there someone that had the same problem? Or does the Ducati 6pole stator have a known issue with the purple wire?

I've checked everything else a million times and tried everything i know...always same problem!

 

If i forgot something, please ask.

I hope someone can help me.

Sorry for writing in english... i understand german, but cannot speak or write it very good!

[kebab]

..there are (maybe slightly corroded) other items left:

-black round junction box

-cev light bulb holder / headlight junction

>check these

 

 

 

 

 

[Gio695]

Thank you.

junction box is new, even changed it twice and checked all connections.

bulb holder where cleaner all connections and even changed place for purper wires.

yesterday i even changed the coil with the purple  wire for a third one, and another flywheel. Made an extra ground for the speedobulb and changed the two small lamps again...no luck.

[kebab]

brake switch checked ?

short circuit / wrong earth ?

 

[Gio695]

I suppose it's something shorting out, but i've double checked grounds.

All switches are new by the way.

 

Today i've noticed that if i rev the engine when i put the switch in position 2 the bulbs light up for a second before the engine cuts off.

At idle the engine cuts off immediately.

In position 3 with all lights on and pushing horn or brakelights there are no problems at all at idle...

 

Thank you for thinking with me, all tips are always welcome with this weird problem.

[Gio695]

I've changed the flywheel for a third time, also cleaned all grounds and checked sparkplug gap once again and now all is working. I think both flywheels i used had same problem (to little magnetisme?)
But now i have some kind of knock/trembling sound coming out of top end. I hope its the flywheel thats slightly out of balance and notthing else broke .
At least i now know how to fix the purple wire problem.
Thanx to all for your help.
this topic can be closed
Grtz,
Gio

[clash1]

das polrad macht sicher nicht diese geräusche...

[Gio695]

OK thanx... So probably piston/crank problem?