Has anyone else had issues with picking up a signal on secondary ignition cuircuits on motorcycles specifically?

I have numerous devices including the scope that i have secondary (HT lead clamp type) pickups that dont seem to register a signal. Yet with a COP inductive probe on std ht lead and plug cap systems i can get signal?

Anyone found the same or have any ideas on why this might be?

Found out why i haven't been able to get a signal for all these years.

It appears that the manufacturers have been using unmarked and unspecified anywhere shielded HT leads which is why with std type inductive clamps you get no signal. I used the scope and a cop adapter/extension HT lead but connected to the std plug cap and lead and hey presto waveform was revealed.

Hope this helps others as i never knew the oem HT leads were shielded ::), although make perfect sense now ;D.

Are you scoping CDI or magneto type systems?

A bit of both to be honest and i have only tested this on one bike so will update this if i find any anomolies. But most of what i see is either CDI or Transistorised ignition control.

Anything i should be looking out for?

Olly wrote on Jul 3^rd, 2014 at 2:11am:

Anything i should be looking out for?

Not an expert in this field but anything that radiates high rf interference, there's a reason why the ht leads are shielded [smiley=atomic.gif]

if your going to replace shielded ht leads with non-type, move your computer/laptop slowly towards the bike and see what happens. Does the workshop radio go statically?

Mate tried to scope a funny car and everytime he approached near it the laptop screen went black

Hmm interesting.

I knew they shielded certain parts to stop interferance like some regulator rectifiers and such like. It makes sence that a ht lead would generate a much highter level of interferance than a reg rec.

I never noticed anything at the time & radio and workshop lappy was quite close and i never noticed it having a wibble and the bike ran the same even with the other leads run in series to the std ones. I will monitor it next time i hook up and look for signs of interferance.

I assumed that they used shielded HT leads as normally much of the main loom would run within an inch or so of the coil or ht lead so would be much more exposed to even "normal" levels of interferance than on a std automotive application.

I wouldn't replace the leads with non shrouded type as a repair as that may open a can of worms but for scoping the secondary waveforms i thought it should be ok as long as like you suggest there is no interferance that casues running issues or false/poor readings.

Any other thoughts on possible issues with testing along theese lines?

wow nice find :)