Well, it's odd, but it's fixed (I think). I swapped the condensor out first as it is easiest to do. No different. Swapped the coil next. Still no different. Scratched head a lot. There was 12v at the points and coil, but opening the points made no difference to the coil voltage reading (whereas on cylinder 2&3 coil it did). I disconnected the wire from the points and tried quickly grounding it, got sparks at that wire but there was no spark at the plugs. I traced down to where there's a bullet connector between coil & points, cleaned that up and after quite a few attempts at grounding the points wire then I started getting a spark, put everything back together and it runs aok. Presumably there was enough resistance in that connection to let 12v through but not enough getting through current to trigger the coil. It seems a bit weird though as the points wire seemed to spark decently when grounded, and before it finally did wake up it took a lot of attempts at grounding it.
There is one other connection in that wiring but it is right behind the swingarm pivot. I'd like to have a look it though. I may well just make up a fresh set of wiring and pull it through instead, as I'm not very confident it is fixed properly now.
