no spark - i'm out of ideas

[nicko]

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.

[nicko]

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

[fallenmikethebike]

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

[knackeredMk1]

+1

[pudzie83]

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

[nicko]

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

[fallenmikethebike]

Has the woodruff key sheared on the magneto?
Mike

[jompy]

HT lead wire broken inside ?

[nicko]

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