After a few weeks of untroubled running my 150v suddenly lost all it`s sparks.. all the obvious checks are being done but electrickery is not my strong point. The bike has a battery but i`m unsure if it needs a battery to make a spark, or is the battery just to power lights and horn ? I would like to try wiring battery straight to the coil to see if it works , so... if i run a wire to + (RU ? ) terminal and another from AL terminal to earth will that do it ? or have i got that back to front ?
I 'think' the type of generator fitted to these bikes may need the battery to help provide initial spark, OR, perhaps not if it is fitted with the two way switch mounted under the headlight. This if I remember correctly is similar to Brit bikes that had an emergency start function, you can switch it to the alternative position to bring in an extra part of the generator to start the bike when the battery is flat. However, if your battery is ok and the spark has gone then problem is elsewhere. Try different plug, then lead, cap, or even coil one by one to find the problem. Are connections all good at the points, and make sure that nothing is touching an earth that shouldn't. Very simple electrics, should not be too hard to isolate the issue. Whereabouts are you?
Thanks for your reply, I am in North east (Durham) the switch on the headlight is missing but it is interesting to find out what it `may` do ie act like a brit switch, I have had it sparking and starting by joining two wires from the switch on top of headlight (which is the wrong type) but today it gave up again. I have a wiring diagram so will attempt to figure it out. going to earth somewhere sounds likely .. I have started looking for a box of matches though !!!
I don't think the standard system needs the battery to inspire a spark. It's a magneto type affair which generates it's own power to fire the coil.
From what you've said it sounds like there is a short to earth somewhere.
I'm not 100% because like you electrics are not my strong point, but if you follow the wires from the magneto one should go to the coil.
Disconnect any other wires that are connected to the same pole to ensure any unwanted earth.
Still no spark I'd be looking at the points - gap/timing and clean, and/or the condensor, oh and don't forget to check the plug gap etc.
I know Italian stuff has a bad rep with electrics but it's a pretty basic system and the components - stator, flywheel etc are good quality.