Wiring problem on series 3 LI 125 - HELP

[harps2]

Hi

Newbie here about 80% through rebuild (just replaced cracked kickstart shaft. - thanks for previous help!

Problems with starting -sometimes spark them nothing so tried green wire from stator to earth - no spark so changed condenser, tried again still no spark but brown or blue wire touched to earth - great spark - something wrong here but I have no idea what - HELP please

Thanks in advance

Alan

[Warkton Tornado No.1]

What ‘tools’ do you have @ your disposal?

For instance, there is little point in trying to help you if you don’t have a wiring diagram. Preferably, you should have a workshop manual or Sticky’s guide.

[harps2]

Yes I have stickys and all tools required

[Wack]

Not seen a blue wire on an Italian stator or loom before but brown is from the lighting coils. If you have set the points and fitted a new condensor and fitted the fibre insulators correctly and the terminal on the points is not touching the flywheel, then maybe the LT coil is faulty. I fit a bulb test light on the green to check it's kicking out a voltage.also check the green wire for continuity on both ends.

[Warkton Tornado No.1]

All of the above is good advice & a methodical approach will solve the mystery….plus a bit of luck.

Within the last hour, despite a good spark with two ‘known’ plugs, I couldn’t get mine to fire up after a bit of a revamp on the bench.

So, in desperation(!) I ‘borrowed’ one of the new plugs for different (racing) machines & off she went.

Perhaps in your case, the plug or plug cap may be not all it would appear.

Personally, I’m beginning to lose the amount of trust I had in NGK products as Lodge & Champion seem more reliable sometimes.

[harps2]

Not seen a blue wire on an Italian stator or loom before but brown is from the lighting coils. If you have set the points and fitted a new condensor and fitted the fibre insulators correctly and the terminal on the points is not touching the flywheel, then maybe the LT coil is faulty. I fit a bulb test light on the green to check it's kicking out a voltage.also check the green wire for continuity on both ends.

Sorry its black and brown from each coil - the green is coming from the points

[harps2]

All of the above is good advice & a methodical approach will solve the mystery….plus a bit of luck.

Within the last hour, despite a good spark with two ‘known’ plugs, I couldn’t get mine to fire up after a bit of a revamp on the bench.

So, in desperation(!) I ‘borrowed’ one of the new plugs for different (racing) machines & off she went.

Perhaps in your case, the plug or plug cap may be not all it would appear.

Personally, I’m beginning to lose the amount of trust I had in NGK products as Lodge & Champion seem more reliable sometimes.

Hi I tried different cap, leads and plugs to no avail, I am wondering why the stator wires black and brown (not blue) produce a spark when touching earth but the green (coming from points) doesn't spark at all! ??

[Wack]

The black and brown are for the lights and will spark on an earth as there's voltage present. I run a points system and have found that fine wire plugs help as less voltage is needed to jump the gap.

[harps2]

The black and brown are for the lights and will spark on an earth as there's voltage present. I run a points system and have found that fine wire plugs help as less voltage is needed to jump the gap.

OK so there's nothing unusual with the black and brown wires sparking but no idea why the green doesn't spark - could it be shorting somehow?

[Warkton Tornado No.1]

The long & the short of it is that you should be getting a spark even from the LT side sufficient to become HT via the coil. So, you may well have a ‘short’, a broken wire/intermittent connection, yet another duff condenser, bad earths from ignition to frame (because I bet that’s where you’re shorting to when testing)

You say you’re having problems with starting. Have you managed to start it @ all yet?

[harps2]

The long & the short of it is that you should be getting a spark even from the LT side sufficient to become HT via the coil. So, you may well have a ‘short’, a broken wire/intermittent connection, yet another duff condenser, bad earths from ignition to frame (because I bet that’s where you’re shorting to when testing)

You say you’re having problems with starting. Have you managed to start it @ all yet?

Not started yet after being in country for 13 years - it has fired and coughed spluttered but that was when i had spark at plug - for some reason I have nothing now so gone right back to stator.

Checked again this morning stator wired OK points cleaned again, no wires jammed or shorting but still only sparks from black and brown wire - Nothing from Green ???_ I don't believe its worth moving on to HT coil yet as I don't have sparks from green wire (not sure if this is correct or not) - I am sparking against earth wire from stator housing to HT coil so assume that's OK?

Any more suggestions guys?

[coaster]

Just reading through this thread, you don't mention if you have changed or gapped the points? The points need to be clean and opening and just as importantly, closing properly in order to get a spark. You have mentioned changing the condenser so I would also suspect as already mentioned, that the fibre washers could have been miss-assembled and thus shorting the green to earth. Lambretta points were the bane of my life when I was first into scooters back at the end of the 60's, changing points was hard enough when I was 16 and could still see what I was doing, I hate to think what I would be like now without my glasses plus magnifying glass

[grandpa]

Hi Harps2,
Agree with coaster..You will only get a very weak spark when you hold green wire from stator close to frame .you need to do it in a dark garage..The points need to close as coaster mentions .An analogue meter (not digital) set to ohms connected between green from stator and earth will show a very small deflection as you spin flywheel, lastly check that the engine has a good earth to frame The reason you are getting a bigger spark from lighting circuit is because you have several lighting coils in series but only one LT ignition coil.
Grandpa

[harps2]

Just reading through this thread, you don't mention if you have changed or gapped the points? The points need to be clean and opening and just as importantly, closing properly in order to get a spark. You have mentioned changing the condenser so I would also suspect as already mentioned, that the fibre washers could have been miss-assembled and thus shorting the green to earth. Lambretta points were the bane of my life when I was first into scooters back at the end of the 60's, changing points was hard enough when I was 16 and could still see what I was doing, I hate to think what I would be like now without my glasses plus magnifying glass

OK yes changed points and now after your comment - dismantled points and re-assembled ensuring plastic washers in place correctly - assembled stator to engine, adjusted points gap and checked for spark in dark garage, - SAME brown and black wires produce spark and green NOTHING!

[harps2]

Hi Harps2,
Agree with coaster..You will only get a very weak spark when you hold green wire from stator close to frame .you need to do it in a dark garage..The points need to close as coaster mentions .An analogue meter (not digital) set to ohms connected between green from stator and earth will show a very small deflection as you spin flywheel, lastly check that the engine has a good earth to frame The reason you are getting a bigger spark from lighting circuit is because you have several lighting coils in series but only one LT ignition coil.
Grandpa

Grandpa
OK yes changed points and now after other comments - dismantled points and re-assembled ensuring plastic washers in place correctly - assembled stator to engine, adjusted points gap and checked for spark in dark garage, - SAME brown and black wires produce spark and green NOTHING!

Sorry no meter to test and your comment "only one LT ignition coil" - I am not wired up to coil yet just taking green wire from stator and touching to earth - have I mis-understood you

its 4 pole early series 3 stator and flwheel

[grandpa]

Hi Harps2
On a 6 pole you have 4 lighting coils and one for the LT ignition( low tension) this voltage is then sent to the HT (high tension) coil that produces the spark.Not sure how 4pole stator is wired but looks like one coil for lights and one for ign.A multi meter is a worthwhile tool less than a tenner.you can see if ign coil has a short to ground also check that the curved spring on the points is not shorted to ground..Weak magnets could cause insufficient voltage. .Points type ignition is very reliable and was used for most vehicles for decades before the introduction of electronics.
Good luck you will fix it
Grandpa

[Warkton Tornado No.1]

Increasingly, the problem is indicating an electrical breakdown @ the stator or within the green wire.

Without some means of testing, such as a meter, the only option would appear to be substitution.

My own stators are all six pole so I can’t lend you one to try, otherwise I would.

[Wack]

Personally I'd bin the 4 pole especially with the cast in boss in the flywheel.

[bluebob]

the next time I have an electrical(no spark) problem before I do anything else I will unplug the green wire to the headset,although in my case that would be the green out of the cdi.i know your wiring is different but I guess you may have a green out of junction box to headset for switch or cut out.had similar prob to you,somehow missed the very faint spark LT spark.changed stator which I knew worked .ssame result.then remembered not checked green to ignition,unplugged it,fired up first kick.green to ignition was frayed and going to earth.worth checking,i was convinced no power was coming out of stator,i must have blinked and missed it,good luck

[johnnyXS]

Your 'Blue' wire is probably the original purple wire which has faded over time.
The wires in the loom coming from the stator should be
Green (Ignition coil)
Purple (Lighting)
Pink (Stoplight switch & Lamp)
Brown (Horn)

My first step would be to check that the earth strap between the chassis and the engine is intact and both the fixing points have been cleaned until bright metal.

Next pull all wires out of the rear junction box . You only need 2x green wires to test the ignition
Take a picture or make a drawing of where they all go back but its colour coded so it should be obvious.

Take the green wire from the stator wiring loom and hold it close to the earth strap almost touching and kick the engine over.
If you get no spark... then your problem lies between the stator and junction box. The LT ignition coil on the stator plate is open circuit or shorted or the green stator wire is shorting out or or broken somewhere or your points are not set properly or your condensor is fubar or the green stator wire is being pinched under the stator plate when it was last screwed back and is shorting the green wire . This happened to me ..its easily done .

If you now get a spark the reconnect the green stator wire in the junction box and replace the green wire going to the coil also.
Now kick the engine over and see if you get a spark at the spark plug ?
No? the remove the HT lead plug cap and cut the lead back 1/2" splay the wires put the end of the HT lead next to a good earthing point and kick the engine over checking for a spark. No spark suggest faulty HT lead or HT coil Try a new HT lead first . If you have a spark at the HT lead then its a faulty cap or spark plug.

ps to stop your engine you'll need to short the stator green wire to an earth until the engine cuts out or pull the spark plug cap off with some insulated pliers