Firstly, how it stopped;
did a couple of laps of a small track & engine spluttered & stopped. it seemed to me like it had run out of fuel, topped it up & still wouldn't start, decided it must be the carb blocked. Took carb apart & there was a lot of silty sediment in it (previous run had been very dusty) cleaned carb & it wouldn't start, stripped & cleaned carb again, still no starty. Checked for spark - no one there.

I have put multimeter on two sides of coil & values match up to those given in ar manual (mine's mk3), tried coil & plug on a good battery & get a spark. So concluded it must be PGM, remembered that i can look for a pulse with my oscilloscope & probing the spade input to coil i could see a pulse at about 8 volts. So it's not coil, its probably not PGM, what else could it be!!??

i wuz gonna check ground/earth connection to PGM next but would appreciate any ideas you forumites may have for a possible way forward.

reading 'CDI/ECU Problems' FAQ suggests i should check voltage supply, might try injecting 12v into the loom

Check the kill button for earthing out, bypass it to see if that alters things. Check the key switch.
It's then the dreaded loom search.
Mike

+1

Check the wires on your ignition barrel one of mine corroded and came off

thanks, i eliminated the key switch & kill switch earlier on & when i had it hooked up to sillyscope i saw a spike with ignition on & no spike with ignition off

Has the woodruff key sheared on the magneto?
Mike

HT lead wire broken inside ?

i don't think it'll be ht lead because i can measure a resistance between plug cap and frame