Sf2 Lights playing up

Not necessary to dismantle ignition switch to diagnose your issue. You need a test lamp to verify output from the proper wire out of it. Eliminate the one that comes from the battery. You lamp will light one wire with your lamp when switch is off. Call that your input (B+, probably red). That leaves the two remaining wires to consider. One ought to run the ignition, the other ignition plus the light circuit. Here's where your diagram will come in handy.l So probe the other two while switching the key to position 1 , then 2 and see which or both have output.  Have you looked inside the headlight for the diode? Possibly a black widget that resembles in inline fuse holder. To avoid trying to visually trace the line through the 'spaghetti', you might want a basic multimeter to test a wire point to point (with battery disconnected).
 
3CBRG said:
Not necessary to dismantle ignition switch to diagnose your issue.
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True, but i have seen them where the internal contacts are dodgy. Fault might not show up unless a decent load is put through it. But yes, definitely test it with a multimeter - essential tool.

As for connectors, I agree about those totally shaez things with plastic, designed to make the wires break where they enter the metal part. If I see even ONE of those on a bike, the warning bells go off big time for me.
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Bit late for warning bells!
I sprayed wd40 in the switch.
Took all fuses out of fuse box, cleaned and wire brushed, swopped fuses
I took the headlight lens off to have a look inside the shell  first,  before I even posted the question.
There is no diode inside, or anywhere else either, not that many places one could be hid.
At the moment I'm totally flummoxed,  usually if I look at a circuit diagram long enough, then some sort of understanding begins to form of which wires to start testing, but not this time, yet!
I know the light circuits work, just not at the right time.
The lights did work properly for a while before this occurred.
I will see if I am able to test the switch better.
Is it correct that when using a 4 wire switch with a 3 wire ignition, it's the grey wire that is not used.
I rang Richard Slatter to see if he had switches still, he has but they are all 4 wire and reckons that is what is used as replacements now.
 
All's good, have found the problem.
As I could not work out how to check the ignition switch, I tried another method, by totally removing it and wiring direct across the wires, the problem was the same, which told me the ignition was not causing the issue, so then I started checking the ignition circuit  on the lights  and found a broken wire half way up the frame that powers the lights on the on/off switch.
Big thanks to dellortoman, and the rest of you, I don't have to lie in bed tonight analysing Laverda circuit diagrams in my mind
 
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