Invisible Spark

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mick1
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Posts: 1471
Joined: Sun Dec 04, 2011 7:43 pm
ebay user ID: saxonleaf
Main scooter: Li Avanti 225
Location: York
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Mon Apr 16, 2018 7:57 am

I fitted a new external pick up and a new DC cdi and coil.......all working fine.
I decided to add my "Old" ac ignition as back up. Stator pick-up, LT coil and cdi.
The LT coil and pick-up had been left on the scooter and never touched, the wires simply disconnected.
CDI fitted and all wires connected.
I added a HT lead and suppressor cap to the "old" ac cdi, so if i wanted to swap systems over it was merely a question of pulling one suppressor cap off the spark plug and pushing the other on.

I initially started with the old ac system......no joy starting scooter. I swapped over to my DC system..started 1st kick. tried with the ac again but no joy. I took the spark plug out to check for spark....couldn't see one. Out of interest i swapped back to DC and checked for spark again...still couldn't see a spark ?

This was all outside on my driveway. I wheeled the scooter into my garage, shut the doors, turned off lights (pitch black). Checked again for spark on both systems, still couldn't see a spark. Put plug back in....started 1st kick ? Found the reason for not starting on AC (broken wire on pick-up crimp). Checked again for spark, couldn't see one, but started ok ?

Basically, even in pitch black, i can't see a spark, but with either system (AC or DC) but it starts fine ?

Tried 3 plugs, one brand new, one well oiled and black.

Not a massive problem as the scooter starts and runs fine but any ideas why i can't see a spark ?

Arborman
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Main scooter: RB22
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Mon Aug 13, 2018 9:15 pm

Mmmm had the same issue on another bike yesterday we had it running. It was a bit of a pain to start so we removed the plug to look and decided to check as you were doing absolutely no spark whatsoever we were baffled. Tried other plugs changed the scootronics CDI and still nothing. So put the plug for the hell of it and as yours ,it started first kick but all this with no visable spark.

mick1
registered user
Posts: 1471
Joined: Sun Dec 04, 2011 7:43 pm
ebay user ID: saxonleaf
Main scooter: Li Avanti 225
Location: York
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Mon Aug 13, 2018 9:26 pm

I've come to the conclusion it must be magic...........and left it at that...

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EddieStone
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Joined: Mon Aug 17, 2015 4:13 pm
Main scooter: Lambretta Li 150
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Thu Aug 16, 2018 1:03 pm

Where are you earthing the plug after you've taken it out? Could it be that it's not earthed?

I've had some plugs earth to the side rather than the electrode so you might not see it. I'd have thought you'd be able to see it in the dark though.

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