02-10-12, 09:02 AM
Diagnosis so far:
All fuses are intact, that much I was able to check at the roadside.
"Unfazed": good point about the cam cover being isolated, but more by luck than judgement I'd been checking the spark against a cylinder fin.
The pick-up coil resistance is a healthy 200Ī© and produces a measurable a.c. voltage as the starter spins the engine. So it's not that. And the signal appears on the actual connector for the CDI unit, so it's not getting lost on the way there.
The ignition coils themselves are OK, as is connectivity of the 'cold' end of the coil primaries to the CDI... there are no sparks to any cylinder so it's got to be something common to both sides anyway.
The ignition switch is certainly getting a bit iffy, at least mechanically, but all contacts are working, the speedometer faithfully registered the decline to zero mph :rollinĀ and both coils have 12v present, so it's not the kill-switch or a wiring problem in the supply side.
All the sidestand/neutral/clutch interlock stuff looks OK, and would I think, as His Dudeness suggested, have prevented the starter from being used if the fault lay there anyway. As would a missing supply or ground to the CDI unit.
Why do they make wiring diagrams so difficult to follow? :'(
I spend my working life fixing televisions, switch-mode power supplies and bits of broadcast equipment which have circuit diagrams that cover a hundred A3 pages, yet still find it a struggle to understand a handful of switches and relays when they're represented like this. :wall